# Difference between revisions of "Demod2"

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=== mod === | === mod === | ||

+ | |||

+ | Complete encoder and modulator. | ||

+ | |||

+ | Takes arbitrary data stream as input (LSB first according to HDLC standard), applies CRC and FEC, and outputs modulated baseband. | ||

+ | |||

+ | * Input: 500 bps arbitrary data; becomes 1000 symbols/sec with FEC (where does CRC and HDLC framing code go?) | ||

+ | * Output: 48 kHz 16-bit linear PCM little-endian | ||

+ | |||

=== demod === | === demod === |

## Revision as of 23:54, 26 January 2011

Some random notes about the reference BPSK-1000 reference modem for ARISSat-1 by Phil Karn, KA9Q.

## Overview

The package contains a DSP lilbrary libdspfec.a and various utility programs for testing and demonstration purposes. The included Makefile will build the library and all executables.

### Operational constraints

- The reference implementation uses 48 ksps. For other sample rates the filter coefficients in nyquist.c must be reworked
^{[1]}. It is therefore easier to simple resample to 48 ksps.

## DSP library

libdspfec.a and dsfec.h

## Top level aplpications

### mod

Complete encoder and modulator.

Takes arbitrary data stream as input (LSB first according to HDLC standard), applies CRC and FEC, and outputs modulated baseband.

- Input: 500 bps arbitrary data; becomes 1000 symbols/sec with FEC (where does CRC and HDLC framing code go?)
- Output: 48 kHz 16-bit linear PCM little-endian

### demod

## Utilities

### addcw

### addnoise

### async_hdlc_decode

### bplay

### byteorder

### dist

### gentestdata

### meter

## Test programs

### dotprod_test

### pack_unpack_test

### parity_test

### peak_test

### rand_test

### sq_test

### sub_test

### viterbi27_streamtest

### viterbi27_test

## References

- ↑ dpsk.h line 58-61