I am working on a garage door opener( remote controller) .
I am using AM sender and receiver. The carrier freq. is 455 KHZ .
Before antenna I used a power amplifier ( push pull , with transistor BD 135, BD136)
There is an oscillator in sender , too.
When I connect oscillator to AM sender the amplitude decreases. The out put of oscillator is 2 volts but as I connect it to AM sender it will be 0.5 volts. And when I connect these two parts to amplifier, again we have a decrease in amplitude and there is a noise in the output of amplifier.
How I can eliminate the noise and achieve to a fixed output?
By the way , I have limitation on the size of sender.
I have attached the circuits to the mail
Thank you , Vahid KH
I am using AM sender and receiver. The carrier freq. is 455 KHZ .
Before antenna I used a power amplifier ( push pull , with transistor BD 135, BD136)
There is an oscillator in sender , too.
When I connect oscillator to AM sender the amplitude decreases. The out put of oscillator is 2 volts but as I connect it to AM sender it will be 0.5 volts. And when I connect these two parts to amplifier, again we have a decrease in amplitude and there is a noise in the output of amplifier.
How I can eliminate the noise and achieve to a fixed output?
By the way , I have limitation on the size of sender.
I have attached the circuits to the mail
Thank you , Vahid KH