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

Attached Thumbnails

 

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....