buckaroo
Member level 3
Dear All,
For RF receivers with I/Q channel, LNA-->I/Q mixer-->I/Q LPF-->IQ ADC
digital assisted dc offset cancellation(measure ADC output DC offset-->adjust current steering DAC whose output is LPF input, binary search untill ADC +/- output are close)
Now, the question is, I/Q path DC offset are NOT the same, which mean 2 DC offset cancellation are needed, is that so? or just 1 path DC offset cancellation is enough and apply the dcoc result to the other path(e.g, DCOC for I path, apply I path DCOC result to Q path)?
If the former is a MUST, then there will be IQ mismatch due to the different DC operating point for IQ path?
Thanks a lot!
For RF receivers with I/Q channel, LNA-->I/Q mixer-->I/Q LPF-->IQ ADC
digital assisted dc offset cancellation(measure ADC output DC offset-->adjust current steering DAC whose output is LPF input, binary search untill ADC +/- output are close)
Now, the question is, I/Q path DC offset are NOT the same, which mean 2 DC offset cancellation are needed, is that so? or just 1 path DC offset cancellation is enough and apply the dcoc result to the other path(e.g, DCOC for I path, apply I path DCOC result to Q path)?
If the former is a MUST, then there will be IQ mismatch due to the different DC operating point for IQ path?
Thanks a lot!