Tone-decoder


Posted on Apr 2, 2012

Adding a pair of one shots to the output of a 567 tone decoder renders it less sensitive to out-of-band signals and noise. Without the one shots, the 56Tis prone to spurious output chatter. Other protection schemes, such as feeding back outputs or using an input filter, do not work as well as the one shots. The output of the 567 is high in the absence of a tone and becomes low when it detects a tone. The tone decoder triggers a one shot via an AND gate. The one shot`s period is set to slightly less than the duration of a tone burst.


Tone-decoder
Click here to download the full size of the above Circuit.

When the output of the tone decoder decreases, it triggers the second one shot. The second one shot"s period is set to slightly less than the interval between tone bursts. The flip-flop enables and disables the inputs to one shots so that spurious outputs from the tone decoder do not affect the output.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Bass Guitar Compressor
Interfacing seven segment to microcontroller
Double-ended limit detector
Beat-Frequency Audio Generator
Off lining switching power supply solution of OnSemiNCP107515W low power consumption
the design of the walkie cardiotachometer of MSP430
touch sensor switch using inverters
digital logic purpose of diode in this 555 timer application
rear fog lamp for vintage cars
VHF field strength meter
Battery charger using LM317 regulator circuit
Servoelectric Guitar Project
Oscillations and Regenerative Amplification using Negative Resistance



Top