op25-dev November 2014

op25-dev@lists.osmocom.org

1 participants
2 discussions

Simple RX GRC file
by lukekb＠gmail.com [op25-dev] 24 Nov '14

24 Nov '14

Does anyone have a simple GRC for RX conventional Phase 1 audio? The larger program I am working on is in C and I just want to make sure I have the Gnuradio graph right and tune it before I hard code it into C. It monitors a SmartNet II system, so I don't need Phase 2 or Trunking. If not, is it best to look at the scope.py app in OP25-repeater to figure out what the best blocks are to use for decoding? I am trying to switch over from gr-dsd so everything will be more native. Last dumb question, is it better to use the receive blocks in op25 or op25-repeater. Thanks!

2 7

Re: patches
by ikj1234i＠yahoo.com [op25-dev] 09 Nov '14

09 Nov '14

Russell These patches look really great and I think we should merge them into OP25. The bch check does look like it is redundant but it isn't 100% clear what the "perfect" solution would be anyway. As far as this one: > sample = 32767 * (sample < 0) ? -1 : 1; // * sgn(sample) > > Multiplication has higher precedence than the ternary conditional, so the intent of this code is to ensure that 'sample' is confined to the range [-32K, +32K]. The above line of code would only be executed if there's an overflow (which should not occur, in theory). So if it's greater than 32,767 we want to set it to 32,767 (and similarly for the - case, if it's less than -32K we limit it to -32K). So it does look like it needs a set of ( ) added around everything after the * . For that matter, not sure why it couldn't just be sample = 32767 * sgn(sample); as suggested in the code... Thx Russ! Max

1 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

op25-dev November 2014