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Altera_Forum's avatar
Altera_Forum
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13 years ago

Decimation or re-sampling filter

For a software defined radio, we need to resample down factor 1000x. Specifically, we are bringing in a signal at 20 MSps and then decimating down in real-time to 20 KSps [for processing gain]. H...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

CIC decimators have low resource requirements but a rather smooth filter function in frequency domain. They have been extensively used for SD ADC and are still in recent designs. If a more rectangular frequency domain window is required, e.g. for audio applications, at least the last decimator stage must use a different filter topology or at least a correction filter, as already mentioned.

A detailed discussion of CIC decimators and combinations with other types can be e.g. found in Meyer-Baese dsp with fpga.

Regards,

Frank