If I understand it well you do the following to get rid of the audio_carrier:
interpolate 2x to avoid aliasing
downconvert audio-carrier to zero
highpass to get rid of audio-carrier
downconvert video-carrier to zero
get absolute value(get envelope)
decimate 2xThe above steps can be done in gnuradio with the components which are already
there
interpolator
freq_translating_fir_filter (which you feed high_pass fir filter taps)
multiplication (or another freq_translating_fir_filter with low_pass filter
taps, this way you get a band_filter)
abs
decimator
Is there a way to get these same results w/o interpolating the entire signal? See attached diagram. Can we assume that the significant spectrum of the video component is less than 4 MHz? If so, can we take the incoming signal sampled at 8 MS/s complex do our audio processing to get the audio signal, then filter out audio component, translate the video component and do the video demod?
Thanks
Thom Rainwater
diagram.png
Description: PNG image
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