Re: [Discuss-gnuradio] Confusion about Sample rate

[Marcus D. Leech]

On 05/31/2019 11:21 PM, Jiji Varghese wrote:

I am trying to store WiFi signals samples in a file using file sink block, using GNU radio, for spectrum sensing. I know that a single WiFi channel has a bandwidth of 20-22 MHz. So should I use the sample rate in GNU radio block to 40e6 - 44e6 or can I use a lower value? Can I use 1e6 as sampling rate?

What is the lower bound for the sample rate in GNU block? 

I am confused about giving the sample rate.

J. Varghese

A couple of different issues here:

GnuRadio *generally* deals with *complex samples*.  Complex  sampling satisfies the Nyquist Sampling Criterion in a way that allows you to
  run those samples at a rate == bandwidth (more or less).

Gnu Radio doesn't care, per se, about sample rates, and will pass your request on to the underlying *HARDWARE*.  The hardware will, most
  definitely have limits and policies with respect to sample rate, and to answer the question "what sample rates are allowed" you need to refer
  to the hardware you're using.

If you don't understand what the Nyquist Sampling Criterion is, you should definitely spend some time researching that, and how it relates
  to the kinds of things you might be wanting to do with samples, and why 1e6 is not an appropriate sampling rate for a signal with an
  information bandwidth of 22MHz.