> I want to generate repetitve test signals using a software frequency
>> generator and sound card output.Theset may incorporate simple AM or FM
>> modulation and/or an arbitray waveshape.
>>
>> The problem is the upper bandwidth of the soundcard is limited to
>> around 20KHz at best.
>>
>> My idea is to use some kind of marker (short pulse, voltage threshold,
>> etc.) to denote the desired beginning and end of the generated wave
>> cycle. Then to have an external device that will sample the data
>> between these markers and play it paly repetiively at 1000 times the
>> original sample rate. The software I use can sample as low as 6000
>> bps.
>>
>> IOW if the PC outputs a 20KHz sinewave, the upscaler would convert it
>> to 2MHz. That is the highest frequency I would need.
>
>x1000 is 20MHz. You would need an FPGA driving a high speed D2A.
>
Sorry, I have a night job. I meant the prescaler to be 100x not 1000x. At least I had the 2MHz part right.
Does this allow for another perhaps simpler approach?
Lou Dremer