Re: [Discuss-gnuradio] BPSK to QPSK

[Mattias Kjellsson]

Tom Rondeau wrote:
> On 3/3/2010 7:12 AM, Mattias Kjellsson wrote:
>   
>> amarnath alapati wrote:
>>    
>>     
>>> hi everyone,
>>>
>>>         I am using the programs of DIGITAL-BERT folder to see the bit
>>> error rate pattern versus the SNR. The given programs are for BPSK
>>> scheme. I tried to change it for QPSK Scheme. But seems that I did not
>>> do it right. I am giving the modified code in the programs . Please
>>> help me out......Thanking in advance....
>>>      
>>>       
>> I think that the Costas- and MM- blocks only work for differential
>> encoding... If anyone knows differently, speak now of forever hold your
>> peace ;p
>>
>> //Mattias
>>    
>>     
>
>
> No, the synchronization schemes are not dependent on the type of 
> encoding. They will work for either differential or non-differential. In 
> fact, they are really overkill for differentially encoded modulations....
>
> Tom
>
>   
Hum... I'm glad to hear that, although I thought that the pi- phase
ambiguity of Costas- loops made them unsuitable for QPSK-
constellations... But I guess there is something I'm missing in the code
then?

Come to think of it. As stated in "Practical Costas loop design, J
Feigin", one can track the carrier, but there is a chance that the
carrier will come out of the loop "upside down". Are there blocks that
check for this?

BR
//Mattias