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In August 1973 Ham Radio, WA0JYK used a digital phase shifter in a 75m SSB phasing type receiver that only required the clock to only be divided by 2 instead of 4. The chips were ECL D type Flip Flops and differential Schmitt triggers now out of date, but I was wondering if something like this would help. It would make the clock frequency only half of what is presently used in the Softrock 40.

And I quote from the text, "A single inexpensive IC, a Motorola MC1035P, provides a crystal oscillator, a Schmitt trigger and a differential output amplifier. The differential square-wave outputs from this stage are at the crystal frequency and, of course, 180 degrees out of phase. These square waves are divided by two in a switch-tail ring counter which also provides synchronization to the phase quadrature, regardless of turn on or turn off of the receiver."

He gives the following reference:

G.K. Shubert, WA0JYK, "A Digital 90 Degree RF Phase Shifter," The Electronic Engineer, August, 1971

Attached is a schematic of the phase shifter and a spec sheet on the D type flip flops used.

I don't know if the delays would be matched in something like this or not, or what other problems exist in this kind of design, but I would like to throw it out for discussion. I am sure modern IC's could be obtained to perform the same functions.

Bill, WB5TCO

You can also use a DDS or crystal oscillator running at 2X and put it through a diode doubler that feeds the comparators to turn it back to clean 74HC levels.

Here is an example by Bill Tracey;

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At 06:48 PM 10/13/2005, you wrote:

In August 1973 Ham Radio, WA0JYK used a digital phase shifter in a 75m
SSB phasing type receiver that only required the clock to only be
divided by 2 instead of 4. The chips were ECL D type Flip Flops and
differential Schmitt triggers now out of date, but I was wondering if
something like this would help. It would make the clock frequency only
half of what is presently used in the Softrock 40.

And I quote from the text, "A single inexpensive IC, a Motorola
MC1035P, provides a crystal oscillator, a Schmitt trigger and a
differential output amplifier. The differential square-wave outputs
from this stage are at the crystal frequency and, of course, 180 degrees
out of phase. These square waves are divided by two in a switch-tail
ring counter which also provides synchronization to the phase
quadrature, regardless of turn on or turn off of the receiver."

He gives the following reference:

G.K. Shubert, WA0JYK, "A Digital 90 Degree RF Phase Shifter," The
Electronic Engineer, August, 1971

Attached is a schematic of the phase shifter and a spec sheet on the D
type flip flops used.

I don't know if the delays would be matched in something like this or
not, or what other problems exist in this kind of design, but I would
like to throw it out for discussion. I am sure modern IC's could be
obtained to perform the same functions.

Bill, WB5TCO







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Cecil Bayona
KD5NWA
www.qrpradio.com

I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ...

How about using two of these in series, with some kind of buffer between them?
Then we could use the daughter board all the way up to 30MHz :-)

73 de Anders, SM7TJC


KD5NWA wrote: