Re: [Discuss-gnuradio] Low-pass filter

[Tom Rondeau]

On Mon, Nov 18, 2013 at 10:35 AM, Paul B. Huter <address@hidden> wrote:
> If I want to use a low-pass filter to look at 1MHz blocks of data, is it
> appropriate to use the following parameters:
>
> low pass filter: 500khz
> center frequency: -500khz (for 1MHz, increments of 1MHz for others)
> Taps: firdes.low_pass(1, samp_rate, 500000, 100)
>
> Paul B. Huter

For a low pass filter, you specify the passband bandwidth, but it's a
real-valued filter, so it's symmetric about 0. So, yes, if you set the
bandwidth of the filter to 500 kHz, then the filter will filter from
-500 to +500 kHz.

If you just want to look at 1 MHz of spectrum, I suggest you also
decimate the incoming signal so that you reduce your processing
requirements as well as filter.

Tom