[Elecraft] RIT/XIT

Trevor Day [email protected]
Fri Jan 24 14:50:01 2003


Thanks Lyle and Don, I am happier with straight RF :-)
As a matter of interest, I am replying here to both of your responses 
but have not yet seen my own post on the List yet...weird.
  Trev G3ZYY

In message <[email protected]>, Don Brown 
<[email protected]> writes
>Hi
>
>To add a little more to this all of the pots R1, R2 and R5 are read by the
>same A to D port. Each pot is enabled by grounding the CCW end of one pot at
>a time so the A to D can read the voltage. When the other pots not being
>read are high, the diodes disconnect them so they don't affect the reading
>on the pot being read. Its all a bunch of firmware magic.
>
>Don Brown
>KD5NDB
>
>
>----- Original Message -----
>From: "Lyle Johnson" <[email protected]>
>To: <[email protected]>
>Sent: Friday, January 24, 2003 11:42 AM
>Subject: RE: [Elecraft] RIT/XIT
>
>
>> > To save me bothering Gary again (he's busy enough as it is) is there
>> > anyone out there who can explain how the RIT or XIT offset is applied to
>> > the K2.  I can see it originates from the Front Panel and the voltage
>> > from the pot goes to U3 pin 16, but thats where I lose it.  Any ideas
>> > are most welcome :-)
>>
>> The output of the front panel control is a DC voltage read by an
>> analog-to-digital converter internal to the main PIC processor (U6,
>control
>> board).  The processor calculates the PLL offset settings (applied to the
>> synthesizer chip [U14, RF board] on 5 kHz "boundaries" as well as to the
>DAC
>> [U5, RF board] that drives the PLL reference oscillator) and applies them
>on
>> transmit (XIT) or receive (RIT), as appropriate.
>>
>> 73,
>>
>> Lyle KK7P
>>
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-- 
Trevor Day