Re: MC1496


Ban wrote:
Mohammad.sanei@xxxxxxxxxxxxxx wrote:
i have shown the circuit and think that it is per data ***, is not
it?

well, i have a project by ultrasonic , i have to modulate a
signal(melody) with a carrier and send it via a ultrasonic
sensor(40kHz)
then i have to bulid a circuit as a receiver to get that signals from
ultrasonic sensor with a R type of ultrasonic sensor and demodulate it
and propagate it via a speaker.

i have built the modulator with 1496 but i can not get a proper
output?

Look, with your 3.9k resistors you saturate the output transistors. 2mA of
bias makes 7.8V across , but you bias at 6V, so reduce them to 1k5 and the
Re to 220R. Check the square wave level to be not higher than 300mVpp and
the analog in only 200mV~. You also have to filter the audio or else you get
aliasing, which sounds "inverted" frequency response.
--
ciao Ban
Apricale, Italy

i made a new kind of DSB based 1496, i can get an stable 40kHz carrier
with a good DSB at now, but there is another problem,
i have the melody voice on the output of 1496! i have it even i cut the
60kHz oscillator from 1496, so there is an interferences in the output
of 1496?!

.

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