AD633 analog multiplier IC and AM generation.

[dexterdev]

Hi PF,
I used the circuit shown in datasheet of AD633 to generate AM waves. But the output I got was not correct. I want to why this error comes and explanations will be helpful. I will have to go for BF194 designs else. Here in our labs transistor circuits seldom works. Why I don't know? Please help. I am attaching the circuit and o/p waves.

TIA

-Devanand T

 

[justsomeguy]

This looks like a problem in whatever you're using to simulate a scope.. signals don't just 'end' like that, jump to the side, resume, end again, and jump back. Defective scope software does though.

 

[the_emi_guy]

Looks like your "Y" input is not making it into the AD633. Check connections to pins 3 and 4.

 

[dexterdev]

I am not using any simulation s/w, this is the cro o/p I reproduced by drawing...

 

[the_emi_guy]

The waveform looks like modulation is superimposed (added to) carrier instead of modulating the carrier. This will happen if the carrier is making it into Z but not into Y1. Check your Y1,Y2 connection.

What frequency are you at?

 

[jim hardy]

The picture that appears on my screen shows bottom half of measured output wave shifted right by about seven carrier cycles.
If i shift it left to where it aligns, i see a wave that looks just like "expected".

I would diagnose that as a computer software malfunction or misadjustment.

What kind of device are you using to capture that wave?

I dislike computerized oscilloscopes for basic work.

 

[dexterdev]

I cut copy shifted the image of wave to resemble the wave I got in real CRO...It is not a software generated output.

 

[jim hardy]

What emi guy said...


well, get it working one piece at a time.

Set Em to zero and see if carrier Ec is making it through...

then try very small increments of Em,

is what i'd do.

 

[dexterdev]

will try...

 

[ASHIQUEBABU]

the circuit diagram has no error.