[Discuss-gnuradio] How to control latency

[Daniele Nicolodi]

Hello,

I have a system where I acquire a signal through an Ettus N210 at 200
kHz and I process it through a few GNURadio blocks. Those blocks include
a first low pass filtering and decimation to 1 kHz sampling rate and
further resampling down to 10 Hz or so.

In this configuration the output samples are delivered to the last block
of the flow-graph bunched in packets so that a packet is received every
3 seconds.

This does not seem to depend on the last resampling neither on the
maximum buffer site (set calling `tb.run(size)` where `tb` is the top
block of the flow-graph). I also tried to change the UHD frame size with
the `recv_frame_size`, but it had no effect on the latency.

As I'm trying to implement a control loop, I would like to obtain data
at a real 10 Hz rate from my last block. I think the system should be
able to handle the computing overhead just fine.

How can I accomplish this?

Thank you. Cheers,
Daniele