MT Modulate PAM VI
Receives a sequence of data bits, performs PAM modulation, and returns the modulated complex baseband waveform in the output complex waveform parameter.
PAM modulation involves mapping the input bit stream to PAM symbols (as specified by the PAM symbol map), interpolating by zero-insertion, and applying the pulse-shaping filter to the interpolated I/Q data.
Note Using FIR pulse-shaping filters in modulation VIs may lead to the apparent loss of bits caused by filter delay. Refer to Filter Delay for more information about this effect. Set the flush buffers? parameter to TRUE to offset the effects of filter delay in single-shot operations or in the last iteration of continuous operations. |
input bit stream specifies the sequence of information bits to be modulated.
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PAM system parameters specifies parameter values defining the PAM system. Wire the PAM system parameters cluster returned by the PAM (M) or PAM (Map) instance of the MT Generate System Parameters VI to this cluster. Do not alter the values.
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symbol rate specifies the desired symbol rate, in hertz. This value must be positive. The default is 1.00. |
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pulse shaping filter coefficients specifies an ordered array containing the desired sample-spaced coefficients for the pulse-shaping filter. Wire the pulse shaping filter coefficients parameter of the MT Generate Filter Coefficients VI to this parameter. When generating the filter coefficients, ensure that the value of the pulse shaping samples per symbol parameter of the MT Generate Filter Coefficients VI is equal to the value of the samples per symbol element of the PAM system parameters cluster, which is passed to this VI.
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reset? specifies whether the VI continues modulating using the previous iteration states. The VI resets on the first call and when reset? is set to TRUE. reset? must be set to TRUE the first time this VI is called and whenever you want to restart the modulator. The default is TRUE. |
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flush buffers? forces out samples from the modulated waveform that are affected by the FIR pulse-shaping filter delay. Set this parameter to TRUE during single-shot operations and during the last iteration of continuous operations. The default is FALSE.
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error in (no error) can accept error information wired from previously called VIs. Use this information to decide if any functionality should be bypassed in the event of errors from other VIs. Right-click the front panel error in control and select Explain Error or Explain Warning from the shortcut menu for more information about the error.
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output complex waveform returns the PAM-modulated complex baseband waveform data.
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symbols out returns the array of mapped symbols before pulse shaping is applied. The array represents the complex value of each mapped symbol. |
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error out passes error or warning information out of a VI to be used by other VIs. Right-click the front panel error out indicator and select Explain Error or Explain Warning from the shortcut menu for more information about the error.
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