[hpsdr] Help with DSP please

[maillistrw at optusnet.com.au]

Thanks Alberto,


I did a search using:  “Understanding Digital Signal Processing” and found the following:


http://www.google.com.au/url?sa=t&rct=j&q=understanding%20digital%20signal%20processing&source=web&cd=4&ved=0CGMQFjAD&url=http%3A%2F%2Fcdn.preterhuman.net%2Ftexts%2Fengineering%2FDsp%2FUnderstanding%2520Digital%2520Signal%2520Processing.pdf&ei=ILwGUtq4LsiviQel2ID4Bg&usg=AFQjCNGgYlA2n6VCTvljENUZ7rgSJtMy8w&bvm=bv.50500085,d.aGc


Hope the link works, it is a PDF file and looks to be part or all of the book.


Roderick Wall, vk3yc.



From: Alberto I2PHD
Sent: ‎Sunday‎, ‎August‎ ‎11‎, ‎2013 ‎7‎:‎29‎ ‎AM
To: hpsdr at lists.openhpsdr.org


On 8/10/2013 9:24 PM, Bob Cowdery wrote:



Is there a write up at a block level of SharpDSP because I'm not sure why blocks are ordered as they are. The purpose of most is obvious but I'm a bit confused by the oscillator block which I guess is converting to baseband(?). 
 
 Demodulation is something I don't fully get. I believe the convolution directly demodulates CW/SSB (and from what I remember can convert to baseband as well) but for other modes demod is tacked on the end of the processing.
 When doing the overlap/add method of fast convolution I don't know how one calculates how big the FFT should be or  how many taps the filter should have in relation to the sample block size and what the effect of the choice is. Should a small block size (for reduced latency) have a smaller FFT? I've not found a really good algorithm that explains this and many I found seem to differ in approach so I'm not clear on the correct implementation.
  
Any pointers appreciated.

Bob,

   a detailed answer would take many pages and hours to write it down.
What I can warmly suggest you is this really excellent book, where all of your questions above 
are answered in a clear and tutorial way :

http://www.amazon.com/Understanding-Digital-Signal-Processing-Edition/dp/0137027419

I have it and I am very glad that a friend a few years ago pointed me to it.



-- 
73 Alberto I2PHD
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