Binaural CW Filter?
david cripe <ai9e_qrp@...>
Some years ago Rick Campbell wrote an excellent article for QST describing a 'Binaural Receiver' http://www.arrl.org/files/file/History/History%20of%20QST%20Volume%201%20-%20Technology/QS03-99-Campbell.pdf.
The basic concept is that you use a quadrature mixer for the final IF converter, and the two outputs are fed to left and right headphone channels.
It just struck me that a cheap and dirty version of this should be attained using our Hi-Per-Mite CW filters. If you have one set up for 700 Hz, and another one for 770, or 640Hz center frequency, each feeding the left or right headphone channel, much the same effect is achieved. The different phase shift that each filter has for each frequency will give a sensation of depth, helping the ear pick out signals in a crowded band. I haven't verified this yet, but I will as soon as I get some workshop time.
73 Dave NM0S
Dave,toggle quoted message Show quoted text
I may be proven wrong, but I don't think filters on two different frequencies will give the same effect.
SDR receivers are based on the 90 degrees out of phase signals derived from a quadrature mixture. The Binaral receiver lets the listener do the DSP stuff in the human brain - the SDR receivers use a computer (either in the receiver box or in a computer to do the same processing).
I don't think the same results can be derived by listening to two different audio frequencies (even though they may have phase differences). The brain would have to do Fourier transforms for that to happen.
Not to "rain on your parade", and this is not intended to squelch your ideas, but only to say that if you are successful, it would be something entirely new and not thought of before - but entirely different than the Binaral receiver or other SDR concepts.
If successful, it would be worthy of an article in a major ham magazine.
On 11/1/2016 11:35 PM, david cripe ai9e_qrp@... [4sqrp] wrote:
Some time ago I did purchase the Hi-Per-Mite CW filters.
I never got around to building them since the NE SCAF filters came out.
Then I got hit with COPD and I remember the chip being in foam and wrapped in foil.
I did get to use my friends Hi-Per-Mite and that little kit really worked great.
I'm cleaning up here and amazed what I have and forgot about.
My WIN 7 went out and I just got this WIN 10 Laptop so I'm trying to get the pdf part to open for me.
Any new kits coming down the line??
In a message dated 11/1/2016 11:35:57 P.M. Eastern Daylight Time, 4sqrp@... writes:
toggle quoted message Show quoted text
A cheap and dirty version of a binaural RX would be to use a Softrock with a DDS VFO and a couple audio amps driven by the I/Q outputs if the Softrock. One of our NOGAQRP members (Michael, KD4SGN) did this a year or two ago....it's on my list of things to do.
73 de Lee
On Tue, Nov 1, 2016 at 11:35 PM, david cripe ai9e_qrp@... [4sqrp] <4sqrp@...> wrote:
I recall seeing a similar scheme published in QST or Ham Radio a few decades back.
Some schemes put a LPF on one ear and HPF on the other. More complicated schemes had two BFOs. A signal would produce a high tone in one ear and a low tone in the other. When you “centered” it, both tones were at the same pitch and the signal sounded like it was in the center of your tuning space.
I didn’t find the exact article I remembered, but some similar were --
A Simple, Effective Receiving Aid – QST; February, 1986
Synthesizer for Binaural CW Reception – Ham Radio; November, 1975
Dichotic CW Detector – QST; April, 1983
From: Don Wilhelm donwilh@... [4sqrp]
Sent: Tuesday, November 01, 2016 11:13 PM
To: 4sqrp@... ; david cripe
Subject: Re: [4sqrp] Binaural CW Filter?
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