[SOLVED] Ultrasonic receiver data transmission

[agreatstar]

I am using ultrasonic receiver for ultrasonic data transmission. The circuit diagram is attached herewith. I am getting peaks when transmitter and receiver are perfectly aligned and 1.5 mteres apart. But with increasing distance, reliability falls. Also there are a lot of false peaks which lead to spurious data values. Can anybody please point out any mistake in the circuit? ( I only have a single ended supply and transmitter circuit is working perfectly as I get peaks even at 2-3m but the data transmission fails. Expected data transmission rate is 100 bytes per second).

 

[jiripolivka]

Ultrasonic transmission requires both TX and RX transducers to resonate at the same frequency. Try adding variable capacitor (10-300 pF) in parallel with one transducer, if no improvement, then to the other.
Use a parabolic reflector on one or both sides to increase directivity.

Try checking the waveform with an oscilloscope before the amplifier and after it, to see if no limiting action occurs.