[hpsdr] Technical question

[John Melton]

Hi Alberto,

I think most of us are Reading the data from USB and after processing  
a buffer putting either every result sample into the queue for sending  
to the USB or ever 2nd or 4th depending on the sample rate of 48, 96  
or 192. When that queue has the number of samples needed then they are  
written to the USB.

My first test was to loopback audio from Penelope mic input to Mercury  
using this algorithm.

Regards,

John g0orx/n6lyt

Sent from my iPhone

On 30 Jul 2009, at 13:27, Alberto I2PHD <i2phd at weaksignals.com> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
> Phil Harman wrote:
>>
>> 2) If 1) is true, how should I behave when e.g. the  input data  
>> have a sampling frequency of 96 kHz ? Should I send
>>     an output frame every two input frames, or should I send the  
>> output frames at the same rates of the input ones,
>>     repeating the data if need be ?
>>
>> Always send the data at 48kHz, just discard data at higher rates.
> Hi Phil,
>
>
>   thanks for the answer.
>
> Just to check whether I am getting it right.... suppose I set  
> Mercury for a final downsampling frequency of 192 kHz.
> For this my initial test I don't need the input data, I use the  
> input stream just as a clock.
> Does this mean that I count 4 input frames, and I send one output  
> frame every 4 of them ? This seems to me the
> only way to obtain the needed 48 kHz, as if the data which I want to  
> playback are coming from a WAV file, they do not have an implicit
> arrival rate. Of course they were originally sampled at 48 kHz, but  
> the rate at which I can read a WAV file is of course much
> higher, so I need a way to pace my sending.
>
> Thanks for your patience
>
> 73  Alberto  I2PHD
>
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at openhpsdr.org
> Subscription help: http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
> HPSDR web page: http://openhpsdr.org
> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/attachments/20090730/04065554/attachment-0004.htm>