Lets say I have a narrow band signal between about 100 MHz and 101 MHz and I want to perform a high-resolution spectral analysis.
Why could I not simply use a multiplier to generate an 'f - fr' signal - which, if fr = 100 MHz, would run from DC to 1 MHz?
Is it because the multiplier degrades the phase data of the original signal? If so, how could this be recovered by a quadrature detector, and used by the FT?
Do you simply get a 'real' and 'imaginary' output from the QD, which can passed directly as complex parameters to the FT?
Why could I not simply use a multiplier to generate an 'f - fr' signal - which, if fr = 100 MHz, would run from DC to 1 MHz?
Is it because the multiplier degrades the phase data of the original signal? If so, how could this be recovered by a quadrature detector, and used by the FT?
Do you simply get a 'real' and 'imaginary' output from the QD, which can passed directly as complex parameters to the FT?