Frequency shift for removing spurious spectral components from spectrum analyzer output
AssigneeTRW Inc.
InventorJohn E. Winter
Life of this patent
Estimating the term…
Abstract
Apparatus for eliminating spurious spectral components from a spectral analyzer output signal. An input signal is mixed with two separate local oscillator frequencies separated by a frequency offset value to produce two intermediate-frequency signals, which are processed in spectral analyzers. The outputs of the analyzers are then compared to identify and eliminate any components that do not differ in frequency by the offset value.
Claims12
Apparatus for suppressing distortion components in the output produced by a spectrum analyzer in response to an input signal, comprising:
- a first mixer circuit for receiving the input signal and producing a first IF signal having a spectral distribution shifted in frequency from that of the input signal by an amount f.sub.LO ;
- a second mixer circuit for receiving the same input signal and producing a second IF signal having a spectral distribution shifted from that of the input signal by an amount f.sub.LO +.DELTA.f;
- first and second spectrum analyzers for receiving the first and second IF signals, respectively, and producing first and second spectrum output signals which represent spectral components of the first and second IF signals, respectively;
- and
- output signal processing means for comparing the spectral components in the first and second spectrum output signals and for suppressing any components in the first spectrum output signal which do not also appear in the second spectrum output signal as components that are offset in frequency by the amount .DELTA.f from their respective counterparts in the first spectrum output signal.
Apparatus for suppressing distortion components in the output produced by a spectrum analyzer in response to an input signal, comprising:
- mixing means, for producing from the input signal first and second derived signals, of which the corresponding spectral components are separated from each other by a frequency offset .DELTA.f;
- first and second spectrum analyzers for receiving the first and second derived signals, respectively, and producing first and second spectrum output signals which represent the spectral components of the first and second derived signals, respectively;
- and
- output signal processing means for comparing the spectral components in the first and second spectrum output signals and for suppressing any components in the first spectrum output signal which do not also appear in the second spectrum output signal as components that are offset in frequency by the amount .DELTA.f from their respective counterparts in the first spectrum output signal.
Dependencies are inferred from the claim text.