Re: 122GHz antennas


Andy G4JNT
 

Modify the PIC code to reprog the synth in response to an input line.   if you move the frequency sufficiently far away. must surely be able to get outside the passband of measuring kit, hence simulating on/off

But why not just stick with FSK?

And wherever try to linearly modulate the amplitude?



On Tue, 19 Nov 2019 at 10:21, Neil Smith G4DBN <neil@...> wrote:

Sadly, there are no I/Q inputs on the 122 chips, but there is a transmit enable.  I don't see any reference to whether that has a Schmitt trigger response or if it is at least slightly analogue and could be used for modulation, with some sort of inverse response curve in a DAC or something?  Even if it has hysteresis, could it be used for an on-off tone modulation?  Could it perhaps be used with pulse width modulation?

Neil G4DBN


From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of KENT BRITAIN
Sent: 19 November 2019 02:52
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] 122GHz antennas

 

Got a question for the group.

 

Having done a lot of work with 94 GHz, I realize just how much fun it is to

align a millimeter system for best performance.   Both focus and

sighting.

 

The plan is to modulate one of the boards with 1000 Hz AM and test on

the antenna range.  Now the HP415 detector can be connected to the 145 MHz

port and dB's directly read.   And a relatively close object to align the sights on.

 

Would AM modulation be as simple as connecting a function generator

(or 555 timer) directly to the I Q inputs and hit both with the 1000 Hz in

phase?    I would expect slightly more output that way vs just the I or Q port.

going logic level high.

 

Kent  G8EMY

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--
Paul Bicknell G8KFW   South Coast UK
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>

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