Re: Question on Gnuradio Polyphase Channelizer Block?

[Ron Economos]

You should probably use an add block instead of Streams to Stream. 
Here's an example flow graph.

http://www.w6rz.net/pfb-filter-10.grc

Ron

On 12/21/20 11:20, George Edwards wrote:
> Hello,
>
> I have three signals routed to the Gnuradio Polyphase Channelizer 
> Block. The system operates at a sample rate of 90 kHz with 3 channels 
> spaced 25 kHz apart. One channel is centered around DC and the other 
> two at +/-25 kHz. The 3 waveforms are routed into a Gnuradio Streams 
> to Stream Block, so that a simple concatenated stream flows into the 
> Gnuradio Polyphase Channelizer. I also set the Channelizer Block to 
> use 120 Taps and provide 3-outputs. Here are my questions on observing 
> the outputs
>
> Q1. I was expecting each output (block set to 3 outputs) to be at the 
> sample rate (90 kHz/3 =) 30 kz in each of the 3-plots. The plots show 
> a sample rate based on the original rate of 90 kHz. Why is this?
>
> Q2. I expected each output waveform to be centered around DC, but they 
> were instead centered around -25 kHz. Why?
>
> Q3. The output bandwidth for each waveform seems a little bigger than 
> the input, why?
>
> I will appreciate any help that assists to point me in the right 
> direction.
>
> Regards,
> George