spec_power()

Returns the integrated signal power (dBm) of a spectrum

Syntax
y = spec_power(spectralData{, lowerFrequencyLimit, upperFrequencyLimit})

Arguments

Name	Description	Range	Type	Default	Required
spectralData	spectral data in dBm		real		yes
lowerFrequencyLimit	lower frequency limit to be used in calculating the integrated power	(-∞, ∞)	real	min(indep(spectralData))	no
upperFrequencyLimit	upper frequency limit to be used in calculating the integrated power	[lowerFrequencyLimit, ∞)	real	max(indep(spectralData))	no

Examples

total_power = spec_power(dBm(Mod_Spectrum), 60 MHz, 71 MHz)
where Mod_Spectrum is the instance name of a SpectrumAnalyzer sink component, will return the integrated power between 60 and 71 MHz.
total_power = spec_power(dBm(fs(Vout[1])), indep(m1), indep(m2))
where Vout is a named node in a Circuit Envelope simulation, will return the integrated power between markers 1 and 2.

Defined in

$HPEESOF_DIR/expressions/ael/signal_proc_fun.ael

Notes/Equations

Used in Circuit Envelope and Signal Processing simulations.
This expression can be used with spectral data of up to 4 dimensions (frequency should be the inner dimension).

The spec_power() function returns the power (in dBm) of a spectrum integrated between the lower and upper frequency limits specified. If no lower (upper) limit is specified, the lowest (highest) frequency in the spectral data is used instead.

The input spectral data must be in dBm. Spectral data can be generated in several different ways, such as applying the fs() expression on voltage or current time domain data or using the SpectrumAnalyzer sink component. The obsolete components
SpecAnalyzer and FFTAnalyzer also generate spectral data.

The fs() expression returns the voltage or current spectrum of the input data and so the dBm() expression should be applied to the fs() output before it is passed to the spec_power() expression. The frequency axis values in the spectral data returned by fs() are in Hz and so if lower and/or upper frequency limits are to be passed to spec_power(), they should be specified in Hz.
Similarly, the SpectrumAnalyzer sink component returns the voltage spectrum of the input signal and so the dBm() expression should be applied to the spectral data generated by SpectrumAnalyzer before it is passed to the spec_power() expression. The frequency axis values in the spectral data generated by SpectrumAnalyzer are in Hz, so if lower and/or upper frequency limits are to be passed to spec_power(), they should be specified in Hz.

On the contrary, the obsolete SpecAnalyzer and FFTAnalyzer sink components can return the spectrum of the input signal in dBm, dBV, or Magnitude (based on the value of their Display parameter). If dBm is selected, then the spectral data generated by these two sinks can be directly passed to spec_power(). Otherwise, the appropriate transformation from dBV to dBm or Magnitude to dBm should be applied first. The frequency axis values in the spectral data generated by SpecAnalyzer and FFTAnalyzer are in the unit specified by their DisplayFreqUnit parameter, so if lower and/or upper frequency limits are to be passed to spec_power(), they should be specified in the same unit.