another possible DiY QRQ CW 'KEYed' SINE WAVE CPO to use for the MUMBLE INPUT

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Jun 20, 2022, 10:33:32 AM6/20/22

to iCW - internet CW

HERE is a VIDEO DEMO of this CPO in action

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Jun 21, 2022, 3:06:19 PM6/21/22

to iCW - internet CW

Here is yet another method for getting a nice sounding CW SIDETONE into the MUMBLE INPUT

using a Raspberry PI, an OPTO-ISOLATOR & a 555 timer chip square wave running continuously...

both the OPTO-ISOLATOR and the 555 TIMER chip are being powered by the PI's gpio pins...

the OPTO-ISOLATOR is "keyed" by an external CW KEYER's RIG KEYING JACK...

which then passes the 555 square wave that is running through the opto-isolator's output pins

and then into the PI's usb sound card's line input...

...HOWEVER...

being a square wave with harsh harmonics and no edge shaping of any kind....this would sound horrible !

so.... this single GSTREAMER SCRIPT depletes every harmonic OUT of the square wave AND then places

a raised cosine edge onto the RISE & FALL time

gst-launch-1.0 -v jackaudiosrc do-timestamp=true ! "audio/x-raw, rate=48000" ! queue ! audioconvert !

ladspa-zamgate-ladspa-so-zamgate attack=.1 release=.1 threshold=-22 ! audiorate ! audioconvert !

audiowsincband mode=band-pass lower-frequency=698 upper-frequency=898 length=567 window=3 low-latency=true !

queue ! audioconvert ! jackaudiosink buffer-time=5000

- this setup operates at near zero latency -

please see the video description notes for more info...

here is the LIVE DEMO VIDEO example of this operation:

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another possible DiY QRQ CW 'KEYed' SINE WAVE CPO to use for the MUMBLE INPUT - uses 7 FREE EURO-RACK MODULEs