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.
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.
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
1 comments:
Click here for commentsWe need the Output in Sinosonidal form , but OUTPUT given by 555 (2nd One ) would be Square Pulse ? Please Clarify ?