pi4 CPO with Raised Cosine Edges: key TLC555 with iambics & FLdigi CW Keyboard - REgenerate CW on pi

TLC555 timer chip square wave oscillator is being 'keyed' (pin 4/pos rail) by a CW KEYER & its iambic paddles AND also being keyed by FLdigi using FLdigi's serial port keying setup via a usb serial port adapter and keying the serial port's RTS PIN Both the CW KEYER and FLDIGI are keying the diode side of an H11F1 FET OPTOisolator chip and the other side of the H11F1 fet's resistance goes LOW and keys [ PIN 4 and POS RAIL ] of the TLC555 square wave oscillator that is set to operate at 7.5Khz (the TLC555 is powered by the pi's GPIO 3.3 voltage) the TLC555 audio output goes the PI4's usb sound card's LINE INPUT and then into the CW REGEN APPs first it goes into a simple bandpass filter set to 7.5 Khz and the output of the BP Filter goes to the sidechain input of ZAMGATE...which when keyed on its sidechain port, allows the sine wave to pass through on its upper port...you set the sine wave generator app to output at whatever cw pitch you want your CW to be... then the output of ZAMGATE's sine wave is shaped by the ATTACK and RELEASE creating a RISE/FALL time ...and the ZAMGATE threshold setting creates the WEIGHT SETTING light or heavy...it up to you according to how you set that control... the output of the shaped CW of ZAMGATE goes to a final audio bandpass filter, set to the frequency of your SINE WAVE GENERATOR app and then to the output of the PI USB SOUND CARD headphone output you can key in 'real time' at 'NEAR ZERO LATENCY', so you can operate your paddles/keys or KEYBOARD and hear your sidetone 'immediately' in the headphones of the pi usb sound card , which is a BEHRINGER UCA222 in this example one of the 'keys' of operating low latency on this pi4 is setting the CPU to "performance" mode, and using JACK AUDIO CONNECTION KIT at a low enough buffer frames/period setting, at 48k (or higher if your sound card allows that) KXstudio REPOs were used to bring in all the LV2 plugins CALF FILTER & SINE WAVE GENERATOR and ZAMGATE https://kx.studio/Repositories

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Comment by Chuck aa0hw on August 4, 2022 at 1:34pm

Raspberry Pi 4 CW NOTE Raised Cosine Generator - QRQ CW Keyboard, paddles & straight key - LIVE demo

this video is a follow up to the previous video here: https://youtu.be/4IpZ6YV4bpA

on this video, the pi4 jack audio connection kit USB SOUND CARD engine buffer frames were lowered from 128 to 64...making it even lower in latency in operating iambic paddles & straight key ...and....in this video we add a QRQ CW KEYBOARD - FLdigi to the iambic paddles & straight key so all 3 morse code instruments are able to be used at the same time at near zero latency


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