Forums

questions about signal processing

Started by Si Diep March 25, 2003
Hi

Is there anyway I can synchronously take sample from
the ADC and processing at the same time. For instance,
I want to sample my signal through the ADC and then
put it in the buffer. Once this buffer is fulled, I
send it to the filter and start processing my data and
send it to the DAC. While doing that, the ADC is still
sampling and filling up the next buffer and wait for
the processing to complete. And the process take this
buffer and continue on with the processing and so on.
And also is it possible for me to use the same clock
for the ADC and the DAC becuase I want to send the
signal back out at the same sampling rate as I get in.

Thank you

Si Diep



RE: [motoroladsp] questions about signal processing

If you are talking about the 56F8xx family, the ADC can be started and synchronized by a QuadTimer.  Arming the ADC "SYNC" input will cause the conversion to start via the QuadTimer.  Also the interrupt service routine for the ADC or QuadTimer can be used to output a new value to a DAC. maintaining synchronism between the ADC Samples and the DAC update.  Using fast-interrupt, or custom interrupt routines, very low latencies can be achieved between ADC sample, and DAC update.

With regard to filling alternate buffers, it seems to me that most algorithms use a "circular" buffer and continuously run the transforms at the same rate as the ADC conversions thus not needing multiple buffers!!!

Also check the motorola App Notes regarding the PWM, ADC, and QuadTimer Synchronization.

Best Regards,
Jerry.

-----Original Message-----
From: Si Diep [mailto:s...@yahoo.com]
Sent: Monday, March 24, 2003 9:50 PM
To: m...@yahoogroups.com
Subject: [motoroladsp] questions about signal processing


Hi

Is there anyway I can synchronously take sample from
the ADC and processing at the same time. For instance,
I want to sample my signal through the ADC and then
put it in the buffer. Once this buffer is fulled, I
send it to the filter and start processing my data and
send it to the DAC. While doing that, the ADC is still
sampling and filling up the next buffer and wait for
the processing to complete. And the process take this
buffer and continue on with the processing and so on.
And also is it possible for me to use the same clock
for the ADC and the DAC becuase I want to send the
signal back out at the same sampling rate as I get in.

Thank you

Si Diep


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