Re: 80dB now but still needs improvement at 1KHz [OT]

Jan Panteltje <alien@comet.invalid> wrote:

[...] >
https://panteltje.nl/pub/audio_90_degrees_phase_shifter_circuit_diagram_
IMG_6958.JPG

Thst is a 90 degrees phase shifter over the speech audio range for
generating I and Q signals for SSB modulation. design is not mine, used
trimpots to test it :-)

After reading through some back issues of 'Rad Com', I had been thinking
along similar lines for generating SSB.  I was also intrigued by the
Weaver method and wondered if modern multi-stage filters between the
inverted and non-inverted audio sidebands  could reduce the audio notch
effect and allow a wider frequency response.

I let my licence lapse many years ago and had been thinking about taking
it out again before the call-sign got issued to someone else.  The
problem is that they need to see my certificate to prove I passed the
Radio Amateurs' Exam and I don't know where to find it.


--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk