use Reverse Image CW method for super low bit rate OPUS CODEC audio over ip on the mumble iCW server

[Chuck aa0hw]

virtually perfect CW NOTEs in spite of using the lowest possible OPUS AUDIO CODEC bitrate on Mumble "8Khz"

- uses the REVERSE IMAGE CW METHOD for injecting silence into an audio stream, representing each CW ELEMENT; breaking up the 150 hertz stream with silent cw element blocks by using a REAGATE DUCKING GATE ENCODER for the transmitter , and a REGATE DUCKING GATE deCODER for the receiver

for more info on iCW, and Morse Code Audio tones OVER MUMBLE see:

https://sites.google.com/site/icwoip/

[Chuck aa0hw]

rEvErSe iMaGe CW MODE - CW ELEMENTS OF SiLENCE - embedded into a pilot tone carrier wave for CW/aOiP

LIVE DEMO OF 3 VLF signals using this method in one mumble channel over the iCW server

notice the glitches on the reverse image GREEN TRANSMIT carrier, and that even with glitches, the RED DECODED actual CW NOTE does not get distorted most of the time

[Chuck aa0hw]

rEvErSe iMaGe CW MODE for Ultra Low bitrate CW aoiP by amr-nb codec - virtually perfect RX CW notes

rEvErSe iMaGe CW MODE(RiCM) via REAGATE DUCKER plugin for both TX and RX outline of procedures:

TX: FLdigi keys the sidechain port on a REAGATE DUCKer plugin and this places CW ELEMENTs of slience into the TRANSMIT CARRIER TONE of 200 hz and sent over ip to receiver by gstreamer script

RX: the RX amr-nb signal 'key's the RX 2nd reagate duckER plugin and this allows a CW SIDETONE to pass through regate while inducing a 5ms rise/fall time on it due to the ultra low bitrate of less the 3 KiB

the audio tones are going to be raspy & harsh if you use audio for the CW TONEs...however, if you inject SILENCE into a 200 hz pilot tone, for the CW elements, you can reproduce the original CW elements and replace the silence with 'perfect' CW audio tones at the receiver

https://gstreamer.freedesktop.org/documentation/amrnb/amrnbenc.html... https://gstreamer.freedesktop.org/documentation/amrwbdec/index.html...

GSTREAMER SCRIPTS used in this demo:

TX

gst-launch-1.0 -v jackaudiosrc ! audio/x-raw, channels=1 ! audioconvert ! audioresample ! amrnbenc band-mode=2 ! rtpamrpay ! udpsink host=(ip address of receiver) port=2222

RX

gst-launch-1.0 -v udpsrc port=2222 ! "application/x-rtp, media=(string)audio, clock-rate=(int)8000, encoding-name=(string)AMR, encoding-params=(string)1, octet-align=(string)1, payload=(int)96, crc=(string)0, robust-sorting=(string)0, interleaving=(string)0" ! rtpjitterbuffer ! rtpamrdepay ! amrnbdec ! audioconvert ! audioresample ! jackaudiosink sync=false async=false

[Chuck aa0hw]

rEvErSe iMaGe CW MODE(riCM) through High Q, tuned, resonant, Ferrite Rod Antennas: over the VLF band

rEvErSe iMaGe CW MODE(riCM) encoder and decoder operating over the VLF BAND via REAGATE sidechain ducking plugins

TX : a 4kHZ 35μS mono-phasic pulse train is allowed to pass through ReaGate EXCEPT for when its Auxilary Input Channel "L" is being 'keyed' by a CW KEYER, which injects CW elements(gaps) of 'silence' into the 4Khz square wave pilot tone

RX : A CW tone generator is at the main input of the 2nd ReaGate, but it is kept from passing through EXCEPT when keyed by the CW ELEMENTS of SILENCE from the TX 4khz signal pilot tone... the riCM RX signal from RX antenna is attached to this ReaGate's Auxiliary Input Channel "L" and when the 4khz tone signal strength falls below the ReaGate threshold sidechain gating control, the suppressed CW TONE is allowed to pass through, with 3 ms of rise & fall time induced into each CW ELEMENT by the ReaGate ATTACK & RELEASE controls

NOTE: when operating through high Q, resonant, tuned, TX/RX antennas, the CW elements tend to get elongated and will usually produce 'soft' and 'blurry' cw audio notes at the receiver.... to restore precision, defined, CW ELEMENTs, instead of sending CW audio tones, CW ELEMENTS made of silence are injected into a 4Khz VLF PILOT TONE... on RX, the gaps of silence in the 4khz pilot tone, are easily converted back into CW AUDIO notes by a REAGATE VST PLUGIN operating in sidechain ducking mode via CW Regeneration methods