Understanding MC1496 Modulator for AM Radio Transmitter Receiver

[mralam]

hi,

i came across this issue while working on a project. I am designing and AM radio transmitter receiver. While doing some research i found that the best way to do it is to use an MC1496 IC i also found the circuit attached to this post as a way to set it up.

Now before i go and build the circuit does anyone have an idea of how the circuit works and how does the MC1496 produces an AM signal?

Is it just a multiplication of the carrier signal with the input signal?

Any explanation will be great.

 

[Averagesupernova]

It's been a while since I've done any work with a 1496. The 1496 is a BALANCED modulator and according to the schematic you've posted it is set up to do just that. It will produce a double sideband suppressed carrier signal. The carrier null adjustment is used to do just what it sounds like. However, in your case you do NOT want to null the carrier. I don't know if you can just tweek the carrier null pot to get what you want or if you would be better off searching for something else. Any AM modulator (no matter what people try to tell you) is circuit that multiplies as you have eluded to. Do a search on AM (especially if you include my username) and you will find at least one lengthly discussion with more than enough disagreement to go around.

 

[mralam]

Thanks for your help. I will do the search and get back to you

 

[Pumblechook]

Just wondering why an AM transceiver as AM is not used much these days? Narrow band FM, Single Sideband or digital modes are the ususal modes for two way communications. Aircraft are one of the few users left using AM. The usual way of producing AM is to 'modulate' the DC supply to the final class C amplifier...high level modulation.. I am not sure an MC1496 will allow modulation anywhere near 100%. As has been said it is a balanced mixer which can be used to generate supressed carrier AM which is usually then filtered to remove one sideband to produce SSB..Single Sideband.

If you use an MC1496 or an another way of modulating at a low RF level following amplifiers will have to be linear.

 

[mralam]

i was going through my dads boxes and found a box full of mc1496 and he asked me to do something with it. I found that i can be used as an AM modulator. And therefore i started researching it. What i need to know is how does it work in terms of hardware. How is the modulation done based on the circuit that i have attached to this post?
In other words i am trying to analyze the circuit and try to undestand how it produces the AM signal.

 

[mralam]

Sorry Averagesupernova i wasnt able to find any of the posts that you have mentioned in an earlier post??

 

[Pumblechook]

http://www.ece.uAlberta.ca/~decorby/lab2_2003T.pdf

 

[Averagesupernova]

Here is the thread I was referring to: https://www.physicsforums.com/showthread.php?t=38928

I finally lost interest. Incidentally, the 1496 is mentioned in the thread. My 'opponent' in the thread has since deleted his username or whatever. I must say I have never been so frustrated in a thread as I was in that one.