added some notes on FreeDB 2400A and 2400B

git-svn-id: https://svn.code.sf.net/p/freetel/code@3329 01035d8c-6547-0410-b346-abe4f91aad63

diff --git a/codec2-dev/README b/codec2-dev/README
index 7f9d831559077b7f3809c8c2a3937f38794442c4..fe0873c9134d2e299da8fc32ca24790c76bdd45c 100644 (file)
--- a/codec2-dev/README
+++ b/codec2-dev/README
@@ -67,15 +67,6 @@ Also see INSTALL for more general building and installing instructions.
 
    $ ./src/c2enc 1300 ../raw/hts1a.raw - | ./src/c2dec 1300 - - | play -t raw -r 8000 -s -2 -
 
-Embedded FreeDV API
--------------------
-
-See freedv_api.h and freedv_api.c, and the demo programs freedv_tx &
-freedv_rx.  Quickstart:
-
-  $ ./freedv_tx 1600 ../../raw/hts1.raw - | ./freedv_rx 1600 - - | play -t raw -r 8000 -s -2 -q -
-  $ cat freedv_rx_log.txt
-
 Programs
 --------
  
@@ -155,3 +146,39 @@ These can be installed using your systems package management system or
 the Octave package management system.  The version number of each
 package is not important.
 
+FreeDV API
+----------
+
+See freedv_api.h and freedv_api.c, and the demo programs freedv_tx &
+freedv_rx.  Quickstart demo using FreeDV 1600:
+
+  $ ./freedv_tx 1600 ../../raw/hts1.raw - | ./freedv_rx 1600 - - | play -t raw -r 8000 -s -2 -q -
+  $ cat freedv_rx_log.txt
+
+FreeDV 2400A and 2400B modes
+----------------------------
+
+FreeDV 2400A and FreeDV 2400B are modes designed for VHF radio.
+FreeDV 2400A is designed for SDR radios (it has a 5 kHz RF bandwidth),
+however FreeDV 2400B is designed to pass through commodity FM radios.
+
+Demos of FreeDV 2400A and 2400B:
+
+  $ ./freedv_tx 2400A ../../raw/ve9qrp_10s.raw - | ./freedv_rx 2400A - - | play -t raw -r 8000 -s -2 -
+  $ ./freedv_tx 2400B ../../raw/ve9qrp_10s.raw - | ./freedv_rx 2400B - - | play -t raw -r 8000 -s -2 -
+
+Note for FreeDV 2400A/2400B the modem signal sample rate is 48kHz.  To
+listen to the modem tones from FreeDV 2400B, or play them into a FM HT
+mic input:
+
+  $ ./freedv_tx 2400B ../../raw/ve9qrp_10s.raw - | play -t raw -r 48000 -s -2 -
+
+Simulate FreeDV 2400B passing through a 300 to 3000 Hz audio path using sox to filter:
+
+  $  ./freedv_tx 2400B ../../raw/ve9qrp_10s.raw - | sox -t raw -r 48000 -s -2 - -t raw - sinc 300-3000 | ./freedv_rx 2400B - - | play -t raw -r 8000 -s -2 -
+
+Links:
+
+  FreeDV 2400A blog post ...: http://www.rowetel.com/?p=5119
+  FreeDV 2400A & 2400B demos: http://www.rowetel.com/?p=5219
+