Not sure if this is the right forum for this kind of question.
I was looking at some of the SDR block diagrams out there, and I notice that some of the design, after the ADC, it uses Hilbert filter to perform the 90 degree phase shift, and at the same time, on the other branch it uses Delay 32 Tap to compensate for the delay incurred by the processing of the Hilbert filter.
Isn't phase shift 90 degrees the same thing as time delay by 1/4 cycle?
Since ADC samples not just a single frequency, but over a chunk of frequency, I am wondering, while at a single frequency, a phase shift and a time delay may not be different, but how is a phase shift over a wide range of frequency band, not have the same effect as a time delay?
Alas, I just don't get it, if anyone can shed some light on this or direct me to a link that talks about this, that'd be great appreciated.
I was looking at some of the SDR block diagrams out there, and I notice that some of the design, after the ADC, it uses Hilbert filter to perform the 90 degree phase shift, and at the same time, on the other branch it uses Delay 32 Tap to compensate for the delay incurred by the processing of the Hilbert filter.
Isn't phase shift 90 degrees the same thing as time delay by 1/4 cycle?
Since ADC samples not just a single frequency, but over a chunk of frequency, I am wondering, while at a single frequency, a phase shift and a time delay may not be different, but how is a phase shift over a wide range of frequency band, not have the same effect as a time delay?
Alas, I just don't get it, if anyone can shed some light on this or direct me to a link that talks about this, that'd be great appreciated.