Frequency Reducer/ Division

Thread Starter

kahafeez

Joined Dec 2, 2008
150
hi all, happy new year....


i need to convert a 14MHz wave to a wave which has a freq between 200 to 450KHz..... keeping the data intact...... how can i do this????


plz suggest the easiest way.....
 

Thread Starter

kahafeez

Joined Dec 2, 2008
150
i had this concept as the last option..... cz one the mixer ic 1495 or 1496 is a bit costly bt that isnt really a problem....

i'll have to design a local oscillator and then gang tune them all..... this i guess would be a mess :(

apart from that i've always been wondering how does the local oscillator detects the incoming freq as it always has to produce incmg freq + 10.7MHz in FM


can someone plz share a schematic of the local oscillator or the whole heterodyne system ?
 

Thread Starter

kahafeez

Joined Dec 2, 2008
150
i just got an idea..... see the attached image.....

will this work??? well, it should.....

can anyone plz tell any part number for an RF amplifier????
 

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beenthere

Joined Apr 20, 2004
15,819
Some looking turned up this circuit - http://www.edn.com/archives/1994/081894/graphs/17di4fg1.htm.

It's regenerative, so care must be taken in construction to get a stable receiver, but it works up in the 14 MHz range.

The 300 KHz separation between the ones and zeroes might be interesting to resolve. A low-Q receiver is the thing. Most superhet IF bandwidths are much less. Designing an IF for 300 KHz would be interesting, but time consuming.
 

bertus

Joined Apr 5, 2008
22,270
Hello,

You say your data is 14.0 Mhz for 0 and 14.3 Mhz for 1.
If you mix 14.3 with these frequecies you will end up with 300 khz and 0.
When you mix with 13.8 Mhz , you will get 200 khz and 500 khz.

Greetings,
Bertus

PS how did you choose the frequencies?
They are in the 20 meter radioamateur band. This run from 14.000 to 14.350 Mhz
The IARU will not be happy when you actually transmit on these frequencies.
The local authorities have to look after the respecting of the band plans.
 
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