MT Calculate Worst Case Scaling Factor (Modulation and Resample) VI

LabView Digital Modulation

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MT Calculate Worst Case Scaling Factor (Modulation and Resample) VI

Calculates the maximum possible peak amplitude, after pulse-shape filtering and resampling, of a waveform. This calculation is based on system parameters for a given modulation scheme.

By using this VI with the NI-RFSG instrument driver, you can ensure that your waveform lies between +1 and –1, which is a requirement for the NI-RFSG peak-power generation mode.

For the frequency modulation schemes ( FSK, MSK, and CPM), there is no known analytical method to calculate the maximum amplitude that accounts for effects such as resampling, filtering, and so on. Empirically, a waveform scaling factor of 0.8 should be sufficient for most of your applications. This value results in a maximum dynamic range loss of about 2 dB on the RF signal generator.

If you receive errors related to this value, your signal might be aliased. For more information about aliasing, refer to the MT Modulate CPM or MT Modulate FSK VI.

Use the pull-down menu to select an instance of this VI.

MT Calculate Scaling Factor (ASK)

Calculates the maximum possible waveform amplitude for the ASK modulation scheme.

MT Calculate Scaling Factor (ASK)

ASK system parameters specifies parameter values defining the ASK system. Wire this parameter to the corresponding system parameters cluster of the MT Modulate ASK, MT Demodulate ASK, or MT Detect ASK VIs.

	samples per symbol specifies the number of samples per symbol in the modulated output complex waveform. For error-free operation, the samples per symbol value must be an even number. The default is 16.
	symbol map specifies an ordered array that maps each Boolean symbol to the desired deviation frequency. The number of ASK levels in the array must be 2^N, where N is the number of bits per symbol. The vector length for the symbol(s) farthest from the origin must be 1.

pulse shaping filter coefficients specifies an ordered array of filter coefficients corresponding to the desired filter response for the pulse-shaping filter used in modulation. The number of coefficients depends on the pulse-shaping filter characteristics specified in the pulse-shaping filter. Refer to the MT Generate Filter Coefficients VI for more information about pulse-shaping filter coefficients.

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.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. 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.
	code identifies the error or warning code. 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.
	source describes the origin of the error or warning. 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.

waveform scaling factor returns the inverse of the maximum amplitude of the I/Q waveform based on the specified system parameters.

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.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. 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.
	code is the error or warning code. 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.
	source describes the origin of the error or warning. 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.

MT Calculate Scaling Factor (PAM)

Calculates the maximum possible waveform amplitude for the PAM modulation scheme.

MT Calculate Scaling Factor (PAM)

PAM system parameters specifies parameter values defining the PAM system. Wire this parameter to the corresponding system parameters cluster of the MT Modulate PAM, MT Demodulate PAM, or MT Detect PAM VIs.

	samples per symbol specifies the number of samples per symbol in the modulated output complex waveform. For error-free operation, the samples per symbol value must be an even number. The default is 16.
	symbol map specifies an ordered array that maps each symbol to its desired level. The number of PAM levels in the array is 2^N, where N is the number of bits per symbol. The vector length for the symbol(s) farthest from the origin is 1.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. 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.
	code identifies the error or warning code. 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.
	source describes the origin of the error or warning. 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.

waveform scaling factor returns the inverse of the maximum amplitude of the I/Q waveform based on the specified system parameters.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. 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.
	code is the error or warning code. 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.
	source describes the origin of the error or warning. 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.

MT Calculate Scaling Factor (QAM)

Calculates the maximum possible waveform amplitude for the QAM modulation scheme.

MT Calculate Scaling Factor (QAM)

QAM system parameters specifies parameter values defining the QAM system. Wire this parameter to the corresponding system parameters cluster of the MT Modulate QAM, MT Demodulate QAM, or MT Detect QAM VIs.

	samples per symbol specifies the number of samples per symbol in the modulated output complex waveform. For error-free operation, the samples per symbol value must be an even number. The default is 16.
	symbol map specifies an ordered array that maps each symbol value to its desired coordinates in the complex plane. The number of QAM states in the array must be 2^N, where N is the number of bits per symbol. The length of the vector for the symbol(s) farthest from the origin must be 1.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. 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.
	code identifies the error or warning code. 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.
	source describes the origin of the error or warning. 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.

waveform scaling factor returns the inverse of the maximum amplitude of the I/Q waveform based on the specified system parameters.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. 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.
	code is the error or warning code. 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.
	source describes the origin of the error or warning. 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.

MT Calculate Scaling Factor (PSK)

Calculates the maximum possible waveform amplitude for the PSK modulation scheme.

MT Calculate Scaling Factor (PSK)

PSK system parameters specifies parameter values defining the PSK system. Wire this parameter to the corresponding system parameters cluster of the MT Modulate PSK, MT Demodulate PSK, or MT Detect PSK VIs.

samples per symbol specifies the number of samples per symbol in the modulated output complex waveform. For error-free operation, the samples per symbol value must be an even number. The default is 16.

symbol map specifies an ordered array that maps each Boolean symbol to its desired coordinates in the complex plane. The number of PSK states in the array must be 2^N, where N is the number of bits per symbol.

differential PSK specifies the status of the differential PSK.

disable (0)	Does not allow bit sequence encoding.
enable (1)	Allows bit sequence encoding.

PSK type specifies the type of PSK modulation.

normal	Sets the modulation type to regular PSK. This is the default value.
shifted	Rotates the constellation by /M each symbol.
offset	Sets the modulation type to offset quadrature phase-shift keying (OQPSK). This modulation scheme is a form of phase-shift keying in which four different phase angles are used. This scheme is sometimes referred to as staggered quadrature phase-shift keying (SQPSK). For offset PSK, the ideal symbol timing for Q is offset by 1/2 of a symbol period from the ideal symbol timing for I. offset is currently only supported for M = 4.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. 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.
	code identifies the error or warning code. 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.
	source describes the origin of the error or warning. 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.

waveform scaling factor returns the inverse of the maximum amplitude of the I/Q waveform based on the specified system parameters.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. 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.
	code is the error or warning code. 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.
	source describes the origin of the error or warning. 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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