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Mystery Object - IR Receiver and PLL Synthesiser?

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bigal

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Hi,

Pretty much first time posting here but I know the is probably the best place to pose this question!
I picked up this little gadget the other day and have spend a good many hours when I should be revising to try and work out what it does. It is in a perspex box labelled "Super Baby J" and features two female F connectors on it (joined together on the PCB) and a power supply input (with bridge rectifier and 7805 regulator on pcb.

There is a IR receiver coupled to a PIC 16f84 microprocessor, which is itself coupled to a LM7000 PLL synth IC which is a key component in radio tuning circuits but is not a tuner in itself, the datasheet for it leaves me dazed and confused.

There are some passives and a few transistors associated with the LM7000 which also has a trace running to both the F type terminals.

The PIC has its crystal and stabaliser capacitors fitted.

Any Ideas, I am thinking along the lines of something which shifts frequency, maybe for using foreign radios in the UK or similar? I can only see it putting something on the RF bus, I figure it would of had a remote for controlling it.
Google is no help on looking up Baby J....

Pics are attached!
- Alex
 

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Hi Al
It's been a long time since your post here ! Whether now relevant or not, here's a reply ! That device is an old cable-box hack which worked with analog tuners.
Pre-digital encryption techniques were varied and one method used was to pre-program a fixed set of frequencies into the tuner of the cable box allowing access to those 'tuneable' channels. The 'premium' channels were out of band and your 'Baby J' is basically a band shifter.
The LM 7000 PLL is acting as a stand-alone tuner whose frequency is selected by the PIC.
Setting up was easy, once connected inline with the incoming RF signal to the receiver, a fresh channel scan would result in all those premium channels being available !
I just found your post here because I have a few of these in the bottom of an old junk box and remembered about them as I have a use for the LM7000. A quick look for its datasheet led me here....
Hope that helps !
Cheers
 
Hi Al
It's been a long time since your post here ! Whether now relevant or not, here's a reply !

Bigal has not logged in here since the day after his post here.

Despite that, welcome to ETO, your post is informative.

JimB
 
Hi Jim
Thanks for the reply ! I posted that just out of sheer randomness !
Thank you for the welcome !
N.
 
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