Voice Bandwidth Filter

Posted on Feb 5, 2014

This circuit passes frequencies in the 300Hz - 3. 1kHz range, as present in human speech. The circuit consists of cascaded high-pass and low-pass filters, which together form a complete band-pass filter. One half of a TL072 dual op amp (IC1a) together with two capacitors and two resistors make up a second-order Sallen-Key high-pass filter. With the

Voice Bandwidth Filter
Click here to download the full size of the above Circuit.

values shown, the cut-off frequency (3dB point) is around 300Hz. As the op amp is powered from a single supply rail, two 10kO resistors and a 10 µF decoupling capacitor are used to bias the input (pin 5) to one-half supply rail voltage. The output of IC1a is fed into the second half of the op amp (IC1b), also configured as a Sallen-Key filter. However, this time a low-pass function is performed, with a cut-off frequency of about 3. 1kHz. The filter component values were chosen for Butterworth response characteristics, providing maximum pass-band flatness. Overall voltage gain in the pass-band is unity (0dB), with maximum input signal level before clipping being approximately 3. 5V RMS. The 560O resistor at IC1b`s output provides short-circuit protection.

Leave Comment

characters left:

Related Circuits

  • New Circuits



    Popular Circuits

    pic volt and amere meter circuits
    serial eeprom interfacing at24c08 with at89c2051
    portable mixer block diagram
    TV remote control Blocker Circuit Jammer using Ic 555 and IR Leds
    Loudspeaking crystal radio receivers
    Spectrum monitor with memory function circuit
    ISO103 ripple reduction circuit diagram