ASK Modulator using 555

ASK means Amplitude Shift Keying. It is one of the type of modulation scheme. It converts high frequency carrier signal into digital data. It transmits bit 1 (logic high) with carrier frequency and bit 0 (logic low) with no carrier.



Circuit Diagram






Circuit Description

This circuit is divided into two sections. 1) 1 KHz Pulse Generator 2) ASK Modulator

Pulse Generator

IC 555 is used to generate pulses at 1 KHz frequency. Freuency generated is depend on RC components. R4, R5 and C3.


F = 1.44 / (R3 + 2 * R4) * C3

This 1 KHz pulse generator output is connected to the reset pin of 555 IC of ASK modulator


ASK Modulator

Here we used 555 Timer IC as Astable multivibrator. If pulse generator output is high then it generates pulses with frequency (F) = 1.44 / (R1 +2 * R2) *  C1. When pulse generator output is low then ASK Modulator output is also low.


Working

Previous
Next Post »

1 comments:

Click here for comments
Unknown
admin
March 12, 2017 at 9:15 PM ×

We need the Output in Sinosonidal form , but OUTPUT given by 555 (2nd One ) would be Square Pulse ? Please Clarify ?

Congrats bro Unknown you got PERTAMAX...! hehehehe...
Reply
avatar