This schema is specified in IEEE Std 1641-20XX, "IEEE Standard for Signal and Test Definition." This schema is a World Wide Web Consortium (W3C) Extensible Markup Language (XML) binding of Annex I Extensible markup language (XML) signal descriptions Clause I.2 XML signal schema definitions" The purpose of this schema is to provide unique types and attributes for IEEE 1641 schemas.This schema uses the W3C XML Schema definition language as the encoding. This allows for interoperability and the exchange of signal component instances between various systems.This schema shall not be modified but may be included in derivative works. Copyright (c) 2009 Institute of Electrical and Electronics Engineers, Inc. USE AT YOUR OWN RISK provides different ways of observing the value All the occurrences of unit must belong to the same quantity (see Table B.4) or, where specified, may be expressed as a ratio quantity. The errlmt is always expressed as a relative range to the value either as a ratio or as plus and/or minus a fixed amount (e.g., "10 V ± 10 mV" or "10 V ± 0.1%") and represents the uncertainty of the value. The resolution property is always held as an absolute value, identifying the granularity of the value. The confidence property is always held as an absolute value, as a ratio, and represents the level of confidence associated with the uncertainty (errlmt). The load_ property is always held as an absolute value. The range property is always held as absolute values, identifying the range of values that may be used, e.g., "10 V range 11 V to 9 V". The value syntax allows for relative range values to be specified (e.g., "10 V range ± 1 V" or "10 V range 1%") where these values are converted to absolute values See range The Physical base class (see Table B.1) is used to describe real physical values. It has a value, an associated dimension described by its units, and an uncertainty. Its value may be constrained. All physical types, e.g., time, voltage, are derived from the Physical class. These derived Physical classes can also offer other interfaces, e.g., a Period may be expressed as both Frequency and Time. The PulseDefn class defines an individual pulse The PulseDefns base class (see Table B.1) is used to define BSC signal properties that consist of a set of pulses. Enumeration data type enumCondition std:enumCondition Enumeration data type enumMeasuredVariable std:enumMeasuredVariable Enumeration data type enumPulseClass std:enumPulseClass Digital data type BSTR std:digitalString The digitalString comprises a list of digital characters separated with delimiters. Each comma ',' or semi-colon ';' is treated as a delimiter between blocks A pin name shall be a contiguous string of characters which may include alphanumeric, hyphen and underscore characters. Pin names may not include a comma, semi-colon, or white-space character namely space, new-line, carriage-return, line-feed, and tab). see Annex B SAFEARRAY(Physical) std:list_ Physical Real data type and Array data type SAFEARRAY(double) std:list_double Integer data type and Array data type SAFEARRAY(long) std:list_int Boolean data type Array data type SAFEARRAY(VARIANT_BOOL) std:list_boolean Data types and Array data type SAFEARRAY(VARIANT) std:list_any Integer data type long std:int Real data type IEEE Std 754™ 2008 [B11] (binary64 format) double std:double Boolean data type VARIANT_BOOL std:boolean Data types VARIANT #any All BSCs originate from classes derived from the SignalFunction base class (see Table B.1). The SignalFunction class is described as a pure virtual class as it can only be used to derive classes rather than to create test objects Sources are the only BSCs from where signals can originate NonPeriodic signals have no implicit period. They identify signals that do not repeat themselves. A Constant signal retains its given level. See Figure B.4 the level of the signal. A Step signal makes a transition from zero to a given level. See Figure B.5 final value of step signal defines when the step transition starts A SingleTrapezoid is a NonPeriodic signal defined by the geometric trapezoid shape. See Figure B.6 value of pulse amplitude time at which trapezoid starts relative to it initialization time taken to reach amplitude time that trapezoid is stable at amplitude Time taken to fall back to transient state Noise may be considered as unwanted disturbances superimposed upon a useful signal, which tend to obscure the signal’s information content. Noise may be genuinely random (as in white noise) or may be pseudo-random. Noise occurs across a range of frequencies and can be characterized by amplitude; it may take the form of a Sensor or Source signal. Pseudo-random noise is only of interest as a Source signal. In addition to amplitude, it also allows a frequency and an optional seed to be defined. See Figure B.7 used for pseudo-random noise upper bound frequency bandwidth for transient disturbances A SingleRamp represents a linear transition from 0 to the defined amplitude level during a defined time period. See Figure B.8 final value of ramp signal time for signal to reach final value defines when the step transition starts Periodic signals are signals in which the amplitude value (a dependent variable) changes as a periodic function of time (an independent variable). These signals have an implicit period and frequency. A Sinusoid is a signal where the amplitude of the dependent variable is given by the formula in Equation B.1: Amplitude Frequency initial phase angle A Trapezoidal signal is a Periodic signal that sequentially repeats the SingleTrapezoid. The period is defined by the duration of the SingleTrapezoid. All event times are referenced to local time, which is reset at the start of each pulse. See Figure B.10. value of pulse amplitude time in which the signal repeats itself time taken to reach amplitude time that trapezoid is stable at amplitude Time taken to fall back to transiant state A Ramp signal is a Periodic signal whose instantaneous value follows a linear transition from zero to the defined amplitude during the riseTime, and back to zero during the remainder of the period. In the case that the period is less than the riseTime, the linear transition from zero will stop when the period is reached. See Figure B.11. final level of the signal time is which signal repeats itself Rise Time of ramp signal A Triangle signal is a Periodic signal whose instantaneous value varies linearly and equally about 0. Duty cycle is a ratio between the time for which it increases to its positive value and the time for which it decreases to its negative value. Its parameters are defined by its amplitude, period, and duty cycle. See Figure B.12. maximum amplitude level of the signal time in which signal repeats itself ratio between time taken to increase from its minimum to its maximum value and the time for one period A SquareWave is a Periodic signal whose amplitude (a dependent variable) alternately assumes one of two fixed values of amplitude. The amplitudes are equal to about 0, which is the reference base line. Duty cycle is a ratio between the time for which it remains at its positive value and the time for which it remains at its negative value. Its parameters are defined by its amplitude, period, and duty cycle. See Figure B.13 Amplitude of signal period of signal duty cycle of the wave A WaveformRamp is defined by a sampling interval and a list of values. The WaveformRamp cycles through those values sequentially and infinitely, starting from 0. The width of each window is the same, and each window consists of a Ramp signal. See Figure B.14. amplitude of the output signal where the level factor (in points) the time between each sequence the time between successive (points) outputs level factor of each waveform sample A WaveformStep is defined by a sampling interval and a list of values. The WaveformStep cycles through those values sequentially and infinitely, starting from 0. The width of each window is the same, and each window consists of a line segment (i.e., a step signal). See Figure B.15. amplitude of the output signal where the level factor (in points) the time between each sequence the time between successive (points) outputs level factor of each waveform sample Conditioners take one or more signal inputs and transform them to other signals or, as do Product or Sum, take multiple input signals and operate on these to produce a single signal output. A Filter is a Conditioner that passes a defined set of frequencies from an input signal to produce an output signal. A BandPass Filter passes frequencies within the pass band from an input signal and filters out all frequencies outside of the band. The BandPass Filter is a symmetrical filter in which the rollOff values for the highpass and lowpass transition slopes are equal and opposite. The BandPass filter illustrated in Figure B.16 represents a perfect bandpass filter. Center frequency of the filter's band Bandwidth of filter. Zero implies narrowest band Aratio defining the scaling factor for the signal in the pass band The rate at which the amplitude of the output signal will alter over frequency The maximum allowable variation in the amplitude of the passband signal The maximum allowable variation in the amplitude of the stopband signal The LowPass Filter suppresses all frequencies above the cutoff frequency. Frequencies below the cutoff frequency are passed to the output signal. The LowPass filter illustrated in Figure B.17 represents a perfect step filter. Cut off frequency filter. Zero implies DC offset Aratio defining the scaling factor for the signal in the pass band The rate at which the amplitude of the output signal will alter over frequency The maximum allowable variation in the amplitude of the passband signal The maximum allowable variation in the amplitude of the stopband signal The HighPass Filter suppresses all frequencies below the cutoff frequency. All frequencies above and including the cutoff frequency are passed (with equal gain) to the output signal. The HighPass Filter illustrated in Figure B.18 represents a perfect step filter. See Figure B.18. Start frequency of filter. Zero implies AC Coupled Aratio defining the scaling factor for the signal in the pass band The rate at which the amplitude of the output signal will alter over frequency The maximum allowable variation in the amplitude of the passband signal The maximum allowable variation in the amplitude of the stopband signal A Notch Filter blocks frequencies within the pass band from an input signal and passes all frequencies outside of the band. The Notch Filter is a symmetrical filter in which the rollOff values for the highpass and lowpass transition slopes are equal and opposite. The Notch filter illustrated in Figure B.19 represents a perfect notch (bandstop) filter.. Center frrequency of the filter's notch Frequency band of filter. Zero implies minimum band Aratio defining the scaling factor for the signal in the pass band The rate at which the amplitude of the output signal will alter over frequency The maximum allowable variation in the amplitude of the passband signal The maximum allowable variation in the amplitude of the stopband signal Combiners take multiple input signals and combine them into a single output signal. Sum makes signals from other signals by summing them together. Product makes signals from other signals by multiplying them together. Diff makes a signal from other signals by subtracting the second and subsequent signals from the first signal. Modulator provides facilities to create a modulated signal where the modulation is proportional to the input signal. FM is a modulator where the instantaneous frequency of the sinusoidal carrier varies with the amplitude of the modulating input signal. Amplitude of Sinusoidal Carrier wave Frequency of Sinusoidal Carrier Wave Frequency deviation AM is a modulator where the amplitude of the carrier varies with the amplitude of the modulating input signal. Modulation Index PM is a modulator where the phase of the sinusoidal carrier varies with the amplitude of the modulating input signal. Amplitude of Sinusoidal Carrier wave Frequency of Sinusoidal Carrier Wave Phase deviation Transformation takes a signal and transforms it (e.g., converting it from the time domain to the frequency domain). With SignalDelay, the In signal is delayed to become the Out signal, where the delay is defined by an initial fixed delay and where the delay may change over time. the rate at which the Rate will alter over time (Acceleration) Fixed delay that signal will be delayed (Distance) the rate at which the Delay will alter over time (Speed) Exponential is a transformation that multiplies the input signal with a coefficient that decays exponentially over time. See Figure B.27. value of damping factor E is an exponential operation on a signal. See Figure B.28. Ln is a natural logarithmic (inverse exponential) operation on a signal. See Figure B.29. Negate modifies a signal so that its amplitude is the negative of the In signal amplitude. See Figure B.30 Inverse is the mathematical reciprocal of a signal. See Figure B.31. PulseTrain creates a train of pulses of the In signal by multiplying the input signal with the amplitude of the pulses. list of pulses Attenuator scales the amplitude (a dependent variable) of the In signal and allows both the increase and decrease of the signal. See Figure B.33. Load provides an impedance to load a signal. See Figure B.34. Limit restricts the values of the signal to ± the limit value. limits the absolute value of the signal to +/- limit value FFT (i.e., Fourier transform) characterizes time domain signals in the frequency domain. It is more restricted than the other BSC signal combination mechanisms. It uses a number of samples (which is rounded up to the nearest power of 2), the time over which the signal will be sampled, and the signal to be converted. An EventFunction creates and manipulates events. Events are signals without value information, where the important information is when they become active and inactive. EventSources generate events. Clock generates an event at regular intervals. Each event is active for the first half of the clock period. See Figure B.37. Frequency of the clock. TimedEvent generates an Out event at regular intervals. Each event is active for a specific duration. If the duration is longer than the event interval (Every), the Out event is signaled active at each interval, but never becomes paused. See Figure B.38. the delay time before the first event will be start the duration that each event is active the time interval for each event PulsedEvent generates an Out event in the form of a sequence of timing pulses primarily intended for use in generating Source signals. The sequence consists of a train of N pulses (where N may be any integer greater than 0). Where N is greater than 1, the pulses may be of unequal duration and spacing. The pulse train may be either output once or repeated infinitely and continuously for a periodic timing sequence. See Figure B.39. list of pulses EventConditioner takes a signal or event and outputs the event when the event conditions occur. EventConditioner allows events to be created and modified, based on the action of the events and signals EventedEvent conditioner allows events to be combined to produce complex event streams. EventCount filters out input events to only allow every count input event. See Figure B.41. Identifies the number of events that must happen before a event is generated ProbabilityEvent conditioner generates an event stream based upon the event stream present at the In event. It will replicate the same timing information, but will randomly suppress In pulses. Conceptually, the ProbabilityEvent comprises a random number generator and a comparator. At each event, the comparator compares the random number with the value of the attribute “probability” to determine whether to generate an event in the Out event stream. A seed is included so that the user can reliably reproduce test results. See Figure B.42. The NotEvent conditioner is active when the In signal is not active. See Figure B.43. Logical event conditioners take multiple input event streams and combine them into a single event stream. OrEvent is active when any In events are active. XOrEvent is active when an odd number of In events is active. AndEvent is active when all In events are active. Sensors allow signal characteristics to be measured, monitored, and compared. A Sensor takes an input signal and generates measurement values. Any Sensor can be applied to any signal; however, the resultant value only has meaning when applied to the correct type of signal. Whether the measurement made is of the dependent or independent variable. Current value measured Array of measurements made Number of consecutive measurement to be made. Zero indicates no measurement to be taken and indicates the Sensor is acting as a monitor only Readonly number of measurements currently made Continuous range of independent variable (Time) over which measurement is made. Value against which any condition is checked. This can be either an absolute value (5V) or a ratio value (50%) representing the percentage value between the low-peak and high-peak values. Test made between measurement and nominal value Read Only flag indicating last measurement Pass/Fail Status. If no measurement is taken GO is False Read Only flag indicating last measurement Pass/Fail Status If no measurement is taken GO is False. Read Only flag indicating the last measurement High/Low Status. If no measurement is taken HI is False Read Only flag indicating the last measurement High/Low Status. If no measurement is taken LO is False Upper Limit value against which condition is checked Lower Limit value against which condition is checked reference to a Signal representing signal model of input signal For all Sensors, every time a measurement is taken, the attribute “count” is incremented. Counter is a Sensor that counts when a measurement would be taken, but does not take any specific measurement. Interval measures the interval between the In/Sync event going active and the Gate event going active. Instantaneous measures the amplitude (i.e., value) of the signal in the dimension “type” at specified instances in time. RMS measures the root-mean-square (rms) value of a signal. Average is the arithmetic mean of all the signal values during the gate time. PeakToPeak is the difference between the highest value and the lowest value during the gate time. Peak is the measured value which is furthest away from the mean value. PeakPos is the value obtained by subtracting the mean value from the maximum measurement of the signal during the gate time. PeakNeg measurement is the value obtained by subtracting the mean value from the minimum measurement of the signal during the gate time. MaxInstantaneous measurement is the maximum measurement of the signal during the gate time. MinInstantaneous measurement is the minimum measurement of the signal during the gate time. The Measure BSC measures any control attribute, as opposed to a capability attribute, of a BSC or TSF, or input signal value of a BSC or TSF. Attribute of the signal that is to be measured Decode converts a stream of bits represented by events into data information via bit values. The measurement's resultant variant's datatype Character set used. This attribute allows alternative character set mappings and code pages to be applied Control is a class of signal that modifies the signal model depending on the Select value. The Control inputs (In) represent the various signal alternatives available, which are selected in turn as the selector changes and, if no Gate is provided, an output corresponding to the selected input is produced. If a Gate is provided, the output is only produced when the Gate event becomes Active. SelectIf converts a single channel event stream into a physical signal the digital event stream. SelectCase converts a multichannel digital stream into a physical signal the digital event stream. selector channel mask, identifies which channels of the selector shall be used to select the input , the value can be expressed as a decimal (13) or hex value (0xC) to identify the binary pattern "1101" selecting channels 1,3 and 4.. A value of 0 implies all channels Encode provides a basic digital signal as a stream of bits derived from the data information, where the bit value 0 is represented by the event state InActive or digital L and bit value 1 is represented by the event state Active or digital H. The tri-state/Digital Z/gated Off are all identical and can not generally be deduced from the data information. The information to be streamed, or the URI identifying location of information. The type of the Variant defines the data type. When using XML descriptions, the attribute datatype shall be used to define a valid datatype The number of output channels. Zero indicates that the number of outputs is the minimum required to represents a complete data symbol the number of times the data is output. Zero indicates that the sequence is repeated indefinitely Used in the XML to define the base type of the data. Character set used. This attribute allows alternative character set mappings and code pages to be applied Channels combines multiple signals into a single multiple channel signal List of pin names associated with each channel Digital is a class of signal that represents one of two values (which are sometimes called by names such as true and false, low and high, 1 and 0, etc.), which can be gated off into a tri-state. A digital signal is a collection of one or more event signals, which can be converted into a range of physical signals. SerialDigital provides a (digital) control signal. These signals may take the form of a low signal, a high signal, or no signal (i.e., high impedance). They are defined by the characters L, H, Z, and X (“don’t care”) in a character string. String containing characters 'H', 'L', 'Z', 'X', '0', '1' identifying digital state. Commas or semi-colons may be used to indicate blocks of data Digital Clock Rate Analog Logic High (1) Analog Logic Low (0) Pulse Class type ParallelDigital provides parallel streams of [digital] control signals. These signals may take the form of a low signal, a high signal, or no signal (i.e., high impedance). They are represented by the characters L, H, Z and X in an array of character strings. The output is multi-channeled, and the number of channels is defined by the width of digital statements. where each string String containing characters 'H', 'L', 'Z', 'X', '0', '1' identifying digital state. Commas or semi-colons are used to indicate the start of a new parallel pattern. Incomplete strings are assumed to be padded out with 'Z's to the full pattern width. A comma (or multiple commas) at the end of the string indicates that the final pattern is all 'Z's. Digital Clock Rate Analog Logic High (1) Analog Logic low (0) Pulse Class type Connection is the base class that collects signals into multiple channels. maximum number of channels allowed to be connected TwoWire is a two-wire connection in which the hi terminal represents the hot, or live, side of a circuit and the lo terminal represents the cold, or return, side of the circuit. TwoWireComp is a two-wire connection in which the true terminal represents the true signal for a differential digital signal and the comp terminal represents the complement signal for the differential digital signal. ThreeWireComp is a three-wire connection in which the true terminal represents the true signal for a differential digital signal, the comp terminal represents the complement signal for the differential digital signal, and the lo terminal represents a ground, or screen, connection. SinglePhase is a two-wire connection in which terminal a represents the live connection to one phase of a one-phase (or more) circuit and the terminal n represents the neutral connection to the circuit. TwoPhase is a three-wire connection in which terminal a represents the live connection to one phase of a two-phase (or more) circuit, terminal b represents the live connection to the second phase of a two-phase (or more) circuit, and terminal n represents the neutral connection to the circuit. ThreePhaseDelta is a three-wire connection in which terminal a represents the live connection to one phase of a three-phase circuit, terminal b represents the live connection to the second phase of a three-phase circuit, and terminal c represents the live connection to the third phase of a three-phase circuit. There is no neutral connection to the circuit. ThreePhaseWye is a four-wire connection in which terminal a represents the live connection to one phase of a three-phase circuit, terminal b represents the live connection to the second phase of a three-phase circuit, terminal c represents the live connection to the third phase of a three-phase circuit, and terminal n represents the neutral connection to the circuit. ThreePhaseSyncro is a three-wire connection for use with the three-stator outputs of a Synchro. FourWireResolver is a four-wire connection for use with the four-stator terminals of a Resolver. SynchroResolver consists of up to four connections for use with the rotor terminals of a Synchro or Resolver. A series connection “via” is used when only one connection is required at the test subject. FourWire is a four-wire connection in which the hi terminal represents the hot, or live, side of a circuit, the lo terminal represents the cold, or return, side of the circuit, refHi represents a terminal for a reference associated with the hi terminal and the refLo represents a terminal for a reference associated with the lo terminal. NonElectrical is a connection for use with nonelectrical signals (such as the connection of fluids and gasses). DigitalBus is a connection comprising one or more terminals. One terminal is used for each simultaneous (i.e., parallel) digital data channel. List of pin names associated with each channel Global attributes minInclusive and maxInsclusive in place of the W3C XSD minInclusive and maxInclusive elements, e.g., Global attributes minInclusive and maxInsclusive in place of the W3C XSD minInclusive and maxInclusive elements, e.g., The global attribute "std scriptEngine" may be used. The rule is that the default engine supports the SML definitions until overwritten by a new value. This new value remains in place for the current scope until over-written by a new value. Preferred method of defining inputs. Allows multiple definitions with input signals for In, Gate, Sync or user defined Defines an individual Input as either a system input In, Gate, Sync or user defined. This field overrides any values specified in the legacy signal attribute values of In If used;specifies the type of system input; e.g. In, Gate,Sync. Gate can only appear once in the list of Ins Sync can only appear once in the list of Ins A constant signal retains its given level. A Step signal has two properties: the start time of the transition and the final amplitude level. The step transition is regarded as instantaneous. Before start time, the value is 0; after start time, the value is the amplitude. A SingleTrapezoid may have zero values for any of its properties. The trapezoid is regarded as its geometric shape. Its properties are defined by its amplitude and the times that bound each signal segment of start time, rise time, pulse width, and fall time Noise is the term most frequently applied to the limiting case where the number of transient disturbances per unit time is large. Noise has amplitude, frequency, and seed as parameters, of the type of the dependent variable, and has a recurring pattern as determined by the generating algorithms and the seed. These parameters define the mean frequency and amplitude of the transient disturbances. The pseudo-random effect applies only to multiple sequences of the same implementation, and different implementations will give different pseudo-random values. A seed value of 0 implies true random noise. Therefore, it could be generated from a thermal noise generator and is not necessarily repeatable. The frequency attribute provides the bandwidth of the frequency spectrum of the noise. The use of zero (0 Hz) implies noise is independent of frequencies, i.e., white noise. A SingleRamp takes the form of a linear signal with the transition time defining the event window of that signal. The slope of the linear signal is defined by the difference between the amplitudes divided by the transition time. In a high-to-low transition, the gradient is negative; and in a low-to-high transition, the gradient is positive.during a defined time period. Sinusoid has amplitude, frequency, and phase as parameters. The amplitude has the type of the dependent variable, the frequency is of type Frequency, and the initial phase angle is a PlaneAngle. See Figure B.9. A Trapezoid signal represents the trapezoidal geometric shape. The continuous signal always starts on the rising edge, and the trapezoid is repeated every period even if the trapezoid has not been completed. A Ramp Signal is a periodic signal whose instantaneous value varies alternately and linearly between two specified values. Its parameters are defined by its amplitude, the time to rise from zero and the period. Triangle signal has amplitude and period as parameters. The amplitude has the type of the dependent variable; the period is of type Time. NOTE—The value of the attribute dutyCycle is a ratio, which can include values outside of the range of 0% to 100% (i.e., 0 to 1). The use of values outside of the range of 0% to 100% may have unintended effects upon the signal. SquareWave has amplitude and period as parameters. The amplitude has the type of the dependent variable; the period is of type Time. NOTE—The value of the attribute dutyCycle is a ratio, which can include values outside of the range of 0% to 100% (i.e., 0 to 1). The use of values outside of the range of 0% to 100% may have unintended effects upon the signal. WaveformRamp takes the form of a sequence of linear signals with the sampling interval defining the event window. The slope of the linear signal is defined by the difference between the previous point and the current point divided by the sampling interval. In a high-to-low transition, the slope is negative; and in a low-to-high transition, the slope is positive. The offset is defined by the previous point. WaveformRamp cycles through the points sequentially and continuously. WaveformStep takes the form of a sequence of constant signals. The level of the constant signal is defined by the points, and a transition in level occurs at each increment of the sampling interval. WaveformStep cycles through the points sequentially and continuously. In the case of the pure filter, the output (eout) is given as defined in Equation B.2 and Equation B.3: In the case of the pure filter, the output (eout) is given as defined in Equation B.4 and Equation B.5: In the case of the pure filter, the output (eout) is given as defined in Equation B.6 and Equation B.7: In the case of the pure filter, the output (eout) is given as defined in Equation B.8 and Equation B.9: Figure B.20 shows the sum of two sinusoidal signals, one with an amplitude of 1 V and a frequency of 30 Hz and the other with an amplitude of 1 V and a frequency of 960 Hz. Figure B.21 shows the product of two sinusoidal signals, one with an amplitude of 1 V and a frequency of 30 Hz and the other with an amplitude of 1 V and a frequency of 960 Hz). Figure B.22 shows the difference between two sinusoidal signals, one with an amplitude of 1 V and a frequency of 30 Hz and the other with an amplitude of 1 V and a frequency of 960 Hz. The instantaneous frequency of a signal is defined as rate of change of φ (dφ/dt). For FM, the general solution is given as defined in Equation B.10: The formula for AM signal is given in Equation B.12: The formula for PM signal is given in Equation B.14: SignalDelay can be applied to both signals and events. The SignalDelay can be used for two distinct operations on the input signal: 1) Delay signals (delay) 2) Change the time base (rate, acceleration) Both these operations can be combined into a single SignalDelay. The delay at time t (td) between the input and output is calculated from the initialization time (t0) as defined in Equation B.16: Any signal may be damped over a given time, according to a floating-point damping factor. An Exponential is determined by the damping factor, using the expression e-t/τ, where τ is equal to the damping factor. The output of the signal may be expressed by Equation B.17: The output of the signal may be expressed by Equation B21: The output of the signal may be expressed by Equation B.18: The output of the signal may be expressed by Equation B.19: Figure B.32 shows the creation of a PulseTrain where the In signal is a sinusoid of amplitude 1 V with a frequency of 30 Hz and the pulses are defined by the PulseDefns [(0.2, 0.5, 0.5), (0.4, 0.3, 0.5)]. The default repetition value of 0 is assumed. The output of the signal may be expressed by Equation B.20: Load provides an impedance, defined in terms of resistance and reactance, which can load a signal. The Load does not modify a signal but is used to indicate an impedance required to ensure the correct operation of a signal at its point of connection. It is not to be used as a circuit element, in which case a Constant of type Impedance may be used. Limit has a generic type. Therefore, using a Limit(Voltage) on a voltage signal limits the signal voltage. Using a Limit(Current) on a voltage signal restricts the voltage to limit the current using the equation V=IR. Using Limit(Power) restricts the voltage to limit the power using the expression I.V. Figure B.35 shows the effect of a limit of 0.90 V on a sinusoid of amplitude 1 V and frequency 30 Hz. The number of samples used is always the next power of 2. FFT converts time to frequency domain signals, useful for measuring frequency characteristics or performing signal analysis. The FFT returns the magnitude of the value of the signal within each frequency band, where the frequency band is defined by 1/interval, and the axis defined from 0 Hz to the Nyquist frequency defined by half of the sampling frequency (samples/(2 × interval)). FFT loses any signal phase information because it provides only real values and does not provide any complex components. NOTE—the use of the FFT as a transform is deprecated, as it is no longer considered to be a transformation of a signal, but a method of providing the characteristics of a signal in the frequency domain. Signal transformation is inherent in the standard for related physical types and reference types (see B.3.3). Figure B.36 shows the FFT of a phase-modulated signal where the carrier has a frequency of 960 Hz with an amplitude of 1 V and the modulating signal has a frequency of 30 Hz. Clock generates an event at regular intervals. Each event is active for the first half of the Clock period. TimedEvent generates an OutEvent at regular intervals. Each event is active for a specific duration, if the duration is longer that than the event interval (Every) the OutEvent is signaled Active at each interval but never becomes Paused. Changes in state (e.g., pulse start and stop) are specified from t = 0. Cycling is facilitated by resetting the time (t) to 0. EventedEvent uses multiple inputs to successively enable and disable its own output. The first input (In(at=1)) is regarded as the enable event; subsequent inputs are regarded as disable inputs. The output is enabled (i.e., active) when the input goes active. If a second input is assigned, the output is disabled (i.e., inactive) when the second input goes active. The output is then enabled (i.e., active) when the first input goes active again, and so forth. If multiple inputs are assigned, the behavior is determined by cascading the inputs through multiple EventedEvent pairs. The EventCount counts events and produces an event when count events are received. The EventCount acts as an event divider in which the divider is dependent on the value of the count property ProbabilityEvent filters out a proportion of input events. The number it lets through is determined by the probability event. The bigger the ratio, the more events pass through; the lower the ratio, the more events are filtered out. ProbabilityEvent filters out complete active sections regardless of their length. NOTE—The value of probability is a ratio, which can include values outside of the range of 0% to 100% (i.e., 0 to 1). The use of values outside of the range of 0% to 100% may have unintended effects upon the signal. The NotEvent is Active when the In Signal is not Active The OrEvent is Active when any in events is Active The XOrEvent is Active when an odd number of in events is Active The AndEvent is Active when all in events is Active For all Sensors every time a measurement is taken, the 'count' property is incremented. A Counter is a sensor that counts when a measurement would be taken, but does not take any specific measurement. The measurement is taken only when the In event is active and Gate event goes active. The counter is set to 0 every time the In or Sync signal becomes active. If no Gate is present (i.e., unassigned), the interval is measured between consecutive In events going active (e.g., period). If the Gate event is present (i.e., allocated), the interval is recorded when the Gate event becomes active. The measurement is reset when the In event goes active. The Sync event clears the count (count = 0) and resets the measurement. The previous revision of this standard used the name TimeInterval for this BSC. The name is changed to reflect the fact that the measurement may be referenced to any valid independent variable. This standard also supports the name TimeInterval, but the use of the name is deprecated. NOTE—The independent measurement value corresponds to the width of the active signal being monitored. So if no Gate is assigned, it’s the width of the Active state of the In signal. See Interval The instantaneous type value of the signal with respect to the independent variable (e.g., time) is returned. The signal is not sampled over a gate time or Gate. The Gate is used only to indicate when the Instantaneous measurement should be made. NOTE—When measuring the independent variable, the measurement value is the value of the independent variable at the instant that the measurement was taken. The default rms gate time should be a whole number of periods of the input signal to achieve maximum accuracy. NOTE—When measuring the independent variable, the measurement value is the RMS value of the independent variable while the measurement was taken. The default average gate time should be a whole number of periods of the input signal to achieve maximum accuracy NOTE—When measuring the independent variable, the measurement value is the average of the independent variable while the measurement was taken, e.g., Average time when measurement was made, or center frequency of the bandwidth NOTE—When measuring the independent variable, the measurement value is the difference in the values of the independent variable when the (last) maximum and the (first) minimum values of the dependent variable occurred. Peak returns either the PeakNeg or PeakPos which ever has the largest absolute value. NOTE—When measuring the independent variable, the measurement value is the difference in the values of the independent variable when the (last) peak and the average (center) values of the dependent variable occurred, e.g., how far the peak is from the center. NOTE—When measuring the independent variable, the measurement value is the difference in the values of the independent variable when the (last) peak and the average (center) values of the dependent variable occurred, e.g., how far the peak is from the center. NOTE—When measuring the independent variable, the measurement value is the difference in the values of the independent variable when the average (center) and the (last) minimum values of the dependent variable occurred, e.g., how far the peak negative point is from the center. When measuring the independent variable, the measurement value is the value of the independent variable at the instant that the maximum peak occurred. When measuring the independent variable, the measurement value is the value of the independent variable at the instant that the minimum peak occurred. This subclass provides the ability to measure any attribute for any TSF or BSC. The Signal and properties referenced by As and attribute are used to indicate the measurement required. The method of measurement is not defined by this standard. The Measure BSC conceptually compares the actual input signal against all possible allowed reference signals and selects a resultant reference signal that provides the best match. The returned values are the corresponding values of the identified resultant reference signal. The best match is defined as the minimum rms value of the difference between the actual input signal and the reference signal defined by As. Decode measures the digital stream and converts it via a stream of bits into a required (type). Each measurement is collected in the measurements property and the last value read is available through the measurement attribute. The UL, LL or nominal value can be used where the physical value will be initially converted to measurement type prior to any comparison. If the default encoding (UTF-8) is selected and the data is type string (BSTR), the characters will be represented as UNICODE across the runtime call and will be dependent on the encoding of the XML document for XML static models. SelectIf cycles through its In signals starting from In(1) on each subsequent change of the selector event state between Low and High. If the selector enters the X state (tri-state), the output is gated off. If the selector enters the Z state (no signal), the previous output continues.Once started, the initial state of selector is considered Inactive and the initial signal selected for output is In(1). Prior to starting the output is considered to be in the ZRep (No Signal) state. As an example, when there are two Inputs, the selector event state Inactive corresponds to In(1) and Active corresponds to In(2). SelectCase selects the Input that corresponds to the masked Selector value (Active/Inactive state). The mask is converted into bit mask and applied (as an And function) over the Selector digital stream, where channel 1 is LSB. The resulting pattern is converted to a one based index to select the corresponding input signal. When the resultant Selector value exceeds the number of inputs a Z state (tri-state) output signal is provided. When the selector channel is Active it is considered '1' and Inactive is considered '0'. Encode allows any data representation to be packaged up and streamed as a sequence of parallel bits. It turns messages such as "Hello World" into a bit stream represented by an event where the event state represent the individual bit state. Since the width attribute does not necessarily need to match the data information type, the data is converted into a stream of bits and each bit assigned to consecutive channels such that channel 1 is the LSB and the channel number corresponding to the channelWidth is the MSB. In this way the following are equivalent: data="11010100" type="xs:boolean" data="HHLHLHLL" type="digital" data="C4" type="hex" data="212" type="byte". Each pattern is delivered when In goes Active (1,H). If the input becomes tri-state (Gated Off), the output is Gated off Digital signals are unique in that their values do not take on physical values; rather, they take on event states that can be converted into physical values. Channels combines each channel of its input signal into a linear set of channels, optionally identified by the attribute channels to form a multiple channel output. All signal phase information is maintained Gating off turns all output channels to the Z state, prior to the first Sync there is no value on any channel (Null), subsequent Syncs have no effect The characters represent the digital signals as follows: H logic high (or logic 1) 1 logic high (or logic 1) L logic low (or logic 0) 0 logic low (or logic 0) Z high impedance (absence of logic signal) X unknown or indeterminate logic level Where an external clock is provided at In, this becomes the external clock used as the digital clock rate. The internal clock defined by the period attribute is not used The characters represent the digital signals as follows: H logic high (or logic 1) 1 logic high (or logic 1) L logic low (or logic 0) 0 logic low (or logic 0) Z high impedance (absence of logic signal) X unknown or indeterminate logic level Where an external clock is provided at In, this becomes the external clock used as the digital clock rate. The period attribute is not used. The digital string comprises a list of digital characters separated with delimiters, each comma ',' or semi-colon ';' delimiter is treated as a new step. Connection is the base class that collects signals into multiple channels Connection is the base class that collects signals into multiple channels Connection is the base class that collects signals into multiple channels Connection is the base class that collects signals into multiple channels Connection is the base class that collects signals into multiple channels Connection is the base class that collects signals into multiple channels Connection is the base class that collects signals into multiple channels Terminals x, y, and z represent the stator terminals S1, S2, and S3. The stator is connected in a delta format, and the output voltages are developed between x and y, y and z, and x and z. Terminals s1 and s3 are used for the sine output, and terminals s2 and s4 are used for the cosine output. In many applications, only two terminals (i.e., r1 and r2) are required for the R1 and R2 excitation connections of a Synchro or a Resolver unit. This connection is used for series signals (such as the application or measurement of current) where only one terminal is connected to the test subject. This connector is intended for use where the UUT requires four pins for what is effectively a two-wire type of connection, e.g., the UUT has power connections with sense terminals which must be identified separately from the force terminals. The terminals to and from are both used where a fluid flows to and from the test subject. Either terminal may be used on its own if the fluid passes only one way (to or from the test subject). The number of parallel connections is specified by the channelWidth of the signal. Each pin name is associated with its corresponding channel. Ground or signal return connections may be added after the active channel pins. The last ground pin will be used to return any remaining channels without a specified signal return pin. If no return pin is specified a common return is assumed. Each channel is delimited by a single comma or semi-colon character, e.g., for a two channel system (channelWidth = 2), the pinString PL1-1, PL1-2 SK1-2, GND indicates that channel 1 uses connection pin PL1-1, channel 2 uses connection pins PL1-1 and SK1-2, and the common return pin is GND. Physical Type of sIgnal's dependent variable Physical type of signal's independent variable Explicit signal outputs Provided for legacy suppot (See Ins) name of script language or script langauge GUID