Posted on Jan 12, 2013

The circuit allows you to eliminate the vocal portion of an audio signal, while leaving the instru mental portion. The circuit mixes two channels that must be 180° out of phase, so the signals that form the center-stereo image is canceled out. Those signals usually appear in phase. Resistor R3 biases the noninverting input of Ul from a center tap formed by resistors Rl and R4, and capacitor C3. Resistor R4, capacitor C3, and potentiometer R6 form a negative-feedback circuit that establishes the closed-loop voltage gain of Ul at unity.

Click here to download the full size of the above Circuit.

The signal is inverted between the input and output. Signals applied to the right input are coupled to the noninverting input of Ul through C4 and attenuating resistor R5. Resistors R3 and R5 make up a 6 dB attenuator, so once again, there is unity voltage gain between the input and the output. However, the right input signal is not inverted. Therefore, a signal appearing at both inputs is phased out by the circuit and will not appear at the output. Even if the two input signals are at slightly different levels because of different source impedances, you can still adjust for full cancellation by carefully tweaking R6.

Leave Comment

characters left:

New Circuits



Popular Circuits

Hot Swapping the PCI Bus
Water Level Alarm
Infrared Headphone Amplifier circuit
500kHz to 4 MHz Converter
Cmos line receiver
Speech Scrambler Circuit
WSH412 Hall Effect Sensor IC With Thermal Lock Protection And Auto Restart Function
1200 to 6000A-10V three-phase thyristor power regulator circuit plating