[PCR-1000] IF/Mode Results

[David Carr]

Hello all,

A quick explaination for my strange questions and then a summary of my 
findings:
I'm doing some software defined radio research with aquistion cards 
sampling at 1.25Msps.  These input amplifiers on these cards have 
response to 1.6Mhz.  I need a RF front end to downconvert my target 
signals into essentially the baseband so that I can sample them.  
Additionally I need to bandlimit the signals to less than half the 
sampling rate to avoid aliasing.  The PCR-1000 almost perfectly meets my 
objectives.  It can tune from .01-1300Mhz, opening a huge range on 
potential signals, it has a 450khz IF that can be sampled directly by my 
hardware and best of all I can use the internal filters to bandlimit my 
signals for me. 

The simplified PCR-1000 signal path looks something like this.


Ant ---(0-1300Mhz)--->Basic Bandselect Filtering--->1st LO 
Mixer--(266Mhz IF)-->2nd LO Mixer--(10.7Mhz IF)-->Point A

Point A--->Selectable 230khz/50khz Bandpass filter--->3rd LO 
Mixer--(450khz IF)--->Point B

Point B--->Selectable 2.8khz/6khz/15khz/"bypass" Filter--->(AM, SSB, FM 
demodulators)

A detailed look/better picture can be obtained on page 4-1 in the 
PCR-1000 Service manual available at Patrik Norqvist's site 
(http://w1.316.telia.com/~u31626584/dl/index.htm)

Tapping the IFs: (see page 4-2 in above service manual for accompaning 
diagrams)

10.7Mhz -> The output of buffer amp Q85 will provide a quite wideband 
signal.  A 230khz/50khz bandlimited signal could be picked up off of the 
output of IF amp Q39.

450Khz->The output of  buffer amp Q49  should provide a 
230khz/50khz/15khz/6khz/2.8khz bandlimited signal at a decent level.

The question about modes was to determine if it was possible to select 
230khz for the 10.7Mhz bandpass filter and select the filter bypass for 
the 450khz IF section in order to get my desired 250khz wide signal at a 
tractable 450khz.

Hope this is useful to someone.
73s
David Carr
KD5QGR



Max Jens Jensen wrote:

>Hello David
>
>
>>>Is it possible to set the PCR1000 to the 230khz filter width 
>>>in any mode 
>>>other than WFM?  If so, what software can do it?
>>>
>
>With Talk PCR it can be set in any mode.
>
>Regards Max
>
>
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