Phase offset as measured against what, and how would that matter for a 
not-phase-sensitive modulation?



Sent from my iPhone

> On Jun 22, 2020, at 11:39 PM, Kevin Hung <[email protected]> wrote:
> 
> 
> Just my guess. The rx IQ samples are rotated by a constant phase offset.
> 
>> On Mon, Jun 22, 2020 at 9:53 PM Marcus D. Leech via USRP-users 
>> <[email protected]> wrote:
>> On 06/22/2020 09:14 PM, Ernest Poletaev via USRP-users wrote:
>>> Hello everyone,
>>> 
>>> I'm new to SDR and trying to implement transmission with AM Modulation 
>>> using uhd library with B205mini board.
>>> 
>>> Currently I have following procedure:
>>> 
>>> Set RX and TX parameters for RF frequency, channel 0
>>> Set sampling frequency to 1M samples per second
>>> Set RX and TX gain
>>> Receiving as sc8, sc8
>>> Transmitting as fc32, sc8
>>> 
>>> -loop:
>>> 
>>> Receiving:
>>> 
>>> As usual with AM demodulation and it is working
>>> 
>>> Transmitting:
>>> 
>>> On audio sink get next 4096 samples of 44.1KHz 16 bit PCM raw audio
>>> Convert each 16 bit sample to complex float with Q=[audio sample normalized 
>>> to -1 - 1] and I = 0
>>> Resample (simple interpolation) 44100Hz buffer to 1MHz
>>> Send buffer for transmission
>>> 
>>> -end loop
>>> 
>>> As RX and TX have same frequency I can see data on RF Analyzer, but it 
>>> didn't demodulates to an audio signal.
>>> 
>>> Am I missing something or my assumption is wrong on some steps?
>>> 
>>> Regards,
>>> Ernest
>>> 
>>> 
>>> _______________________________________________
>>> USRP-users mailing list
>>> [email protected]
>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>> 
>> I'm going to suggest that if you're new to SDR and DSP, you might invest the 
>> time to install Gnu Radio, which provides a very rich environment
>>   for not only constructing DSP flows for most popular SDR radios, but also 
>> debugging those flows when they don't work out as you expect.
>> 
>> 
>> _______________________________________________
>> USRP-users mailing list
>> [email protected]
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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