Does anybody have idea where I can find config diagram for dip switch
of this synthesizer? You can see a picture of whole module on
http://www.tvsd.co.yu/synthesizer.jpg . This is a part of Elettronica
Industriale SPA uhf transmitter.

I would try terminate the transmitter in to a dummy load or 30 dB
attenuator, try to measure the carrier frequency with a Frequency
Counter. Take some notes and just write down the measured frequency at
different settings... You may need a Communications Test Set to decode
any Tone Squelch type codes if that's what the Dip Switch Settings are
for???
Other than that, sounds like ya could use some documentation...

On 15 Jan 2005 16:11:47 -0800, (Igor Djokic) put
finger to keyboard and composed:

Does anybody have idea where I can find config diagram for dip switch
of this synthesizer? You can see a picture of whole module on
http://www.tvsd.co.yu/synthesizer.jpg . This is a part of Elettronica
Industriale SPA uhf transmitter.

Why not reverse engineer the area around the IC? Here is the
datasheet:
http://www.alphacron.de/download/hardware/MC145152.pdf

I would think that if you could determine the frequency at one
particular setting, then the other frequencies would follow a
recognisable pattern.

Alternatively, you could calculate all the settings by determining the
main oscillator frequency (pins 26 and 27), the wiring of RA0-2 (are
they all grounded or tied high?), and how the N and A pins connect to
the switch pack. If you can post these data I believe I can do the
calculations for you.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

On Sun, 16 Jan 2005 18:13:09 +1100, Franc Zabkar
put finger to keyboard and composed:

On 15 Jan 2005 16:11:47 -0800, (Igor Djokic) put
finger to keyboard and composed:

Does anybody have idea where I can find config diagram for dip switch
of this synthesizer? You can see a picture of whole module on
http://www.tvsd.co.yu/synthesizer.jpg . This is a part of Elettronica
Industriale SPA uhf transmitter.

Why not reverse engineer the area around the IC? Here is the
datasheet:
http://www.alphacron.de/download/hardware/MC145152.pdf

I would think that if you could determine the frequency at one
particular setting, then the other frequencies would follow a
recognisable pattern.

Alternatively, you could calculate all the settings by determining the
main oscillator frequency (pins 26 and 27), the wiring of RA0-2 (are
they all grounded or tied high?), and how the N and A pins connect to
the switch pack. If you can post these data I believe I can do the
calculations for you.

I suspect IC12 is an MC12017 65/64 prescaler. The A0-A5 count inputs
probably all connect to one end of the switch pack. The remaining
switches probably connect to 4 of the 10 N inputs, the remaining N
lines being tied high or low. If this is the case, then the frequency
step size would be given by Fosc / R, where R is the divider value
stored in the MC145152's internal ROM lookup table. For example, if
the oscillator frequency is 10.24MHz and the RA0-2 inputs are all tied
high, then the divisor is 2048 (see page 6 of the datasheet). This
would give steps of 10.24M / 2048 = 5kHz. The total count produced by
the MC145152's A & N counters is given by ...

Nt = N.P + A where P/P+1 is the value of the external prescaler (64)

Hence the frequency generated at the external VCO is ...

Fpll = 5kHz . (64N + A)

The more general formula is ...

Fpll = Fosc / R . (N.P + A)

To calculate the actual frequency of the *transmitter*, one would need
to know if the next stages involved multipliers and/or mixers.

I believe the switches serve a dual purpose. I suspect they also
connect to 10 of the external EPROM's address lines. The EPROM
probably contains a lookup table of 2-digit UHF channel numbers which
it presents on its 8 data lines. D0-3 and D4-7 probably control each
of the two CA3161E BCD to 7 segment decoder/drivers. If you dump the
contents of the EPROM, you should be able to decode the relationship
of the switches to the channel numbers.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.