[DSP-10] Getting Started on First DSP-10

[Paul Black]

Thanks Perry, 

Do you know of any circuits for mixing the IF on an existing receiver 
down to the lower IF frequency?

Regards.  Paul



Perry Ogletree wrote:

> The "IF" they are talking about is a 19 KHz. or so IF created by 
> mixing the receiver IF (455 KHz. in your example) down to the lower 
> frequency.  The DSP-10 is designed to produce the lower IF for the 
> DSPx or EZKit Lite. Unfortunately, most affordable, commercially 
> available, DSPs will only handle audio frequencies.  Sound cards 
> suffer from the same limitation.
>
> ----- Original Message ----- From: "Paul Black" <paulb at triode.net.au>
> To: <dsp-10 at mailman.qth.net>
> Sent: Wednesday, November 10, 2004 1:27 AM
> Subject: Re: [DSP-10] Getting Started on First DSP-10
>
>
>> I've taken the plunge and ordered the DSPx and the adaptor board from 
>> TAPR. More S/N is always a good thing. As I live in Sydney Australia 
>> it will take about two weeeks to arrive. But hey I'm good at waiting 
>> (well not really).
>>
>> I was reading that the DSPx could be used with the DSP-10 program 
>> without all of the RF hardware. I also read that this could be done 
>> by feeding in the audio out from your receiver. As I am basically a 
>> SWL this seems to me to be a good way to get started. I could then 
>> use the DSP-10 software as a programmable filter to improve the 
>> quality of my received amateur transmissions.
>>
>> As I've been searching around the internet I've also read about a 
>> program called LinRad which works using a sound card. Now here is 
>> where I start to get confused. The LinRad docs talk about needing to 
>> feed the IF output from my receiver into the LinRad program to 
>> perform signal processing, but the DSP-10 program does much the same 
>> thing by feeding in the audio out from my receiver.  How does a PC 
>> soundcard manage to digitize a 455 KHz signal taken directly from the 
>> IF? What is gained by directly processing the IF signal? Can the 
>> DSP-10 do the same sort of thing and take an input directly from the 
>> IF out of a receiver?
>>
>> Cheers.   Paul
>>
>>
>> Perry Ogletree wrote:
>>
>>> I have used the DSPx and it works better than the EZKit Lite board.  
>>> I have not used it with the DSP-10 yet as I am still building it, 
>>> but I have played with the DSPx and the EZKit Lite.  The DSPx is 
>>> based on a later DSP chip in the same family as the EZKit.  You will 
>>> need the customized code from the DSPx site as it uses a different 
>>> ADC/DAC chip (the one the EZKit used is on longer generally 
>>> available).  Also, there was a mix-up of one of the output pins that 
>>> requires a minor wiring change in the DSP-10 harness.  All this is 
>>> detailed via links form the DSPx site.  The overall benefit of the 
>>> DSPx is improved S/N and since it has more "horsepower" it would be 
>>> possible to write your own code that includes advanced modes.
>>>
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