This is a Simple IF signal generator circuit using CMOS IC CD4011-CD4040 and crystal-3.579 MHz into output AM: frequency 455 KHz
In the event of AM radio repairs, basic tools that are usually found the IF signal frequency generator is used to determine the function of various sectors. Which these circuits are often used transistors, built frequency. But we use innovative circuit used IC and crystal as circuit in Figure 1.
The working starting at IC1/1-IC1/3, R1-R2, C1-C2 and crystal are connected as the square wave frequency generators circuit. Which has a frequency of 3.579 MHz. This frequency will out to pin 10 of IC1/3, before in to pin 12 and pin 13, then out to pin 11 of IC1/4 is finally.
In the section of IC1/4 that see will be connected as a buffer circuit to serve as a buffer. between IC1/3 and IC2 Not interfere with each other.
The frequency 3.579 KHz at IC1 will be connected to pin 10 of IC2 acts as the frequenct divider by value 2 to the power of three. (8). Which this IC2 will have the ability to Division, Up to 2 are 12 (4096).
After dividing the frequency will be reduced to 447.4 KHz. Which error of the frequency 455 KHz is 2 percent out to pin 6 of IC2. Then will pass the low pass filter circuit of 3 set. To filter harmonics On leaving before will appears at output for use.
By output will be a sine wave at load 10 Kohms will be size about 35 mVp-p.
How to builds
This circuit is not used a lot of parts so can assemble on a universal PCB board. Then, the wiring for circuit wiring and various components can view of the example in Figure 2. Be carefully for is the polarity of the electrolytic capacitors correctly. Pin of the IC is not an error.
The components layout
Resistors size ¼W +5%
C1, C2_______22pF 50V____Ceramic
C3, C4_______0.1uF 50V____Polyester
C8__________0.001uF (102) 50V___Polyester
IC1_________CD4011___Quad 2-Input NOR Buffered B Series Gate
IC2_________CD4040___12 Stage Binary Ripple Counter DIP-16
XTAL1-crytals 3.579 MHz______1 pcs.
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