sea murmur simulator

70 sea murmur simulator 2V The heart of the circuit is the "mur- mur source" consisting of Ti and R 10. This produces a signal which is o amplified in voltagecontrolled ampli- fier Al and the following external AF amplifier. Transistor T2 is used as a current- controlled resistance which controls the amplification of Al: the smaller the resistance, the stronger the output signal. u vr 5V The loudness of the surf also depends on the output of the triangular pulse generator consisting of integrator A2 and trigger A3. The output of the trigger is connected to the input of the integrator. Diode D3 is included to prevent the output signal of A3 going negative. This is necessary otherwise the lower parts of the triangular waveform from T1 would then be cut off and instead of a regularly increasing and dying down of surf you would have nothing but interrupted breakers. The slopes of the triangular signal can be adjusted by means of potentiometers P3 and P4. Diodes D1 and D2 allow the pos...