Circuit Diagram For Syndrome Calculation

Circuit Diagram For

Syndrome Calculation

 

Circuit Components

·        4017 ( 5- STAGE JOHNSON COUNTER)

·        40374 ( OCTAL D- TYPE FLIP- FLOP WITH 3- STATE OUTPUTS)

·        4070 (QUADRUPLE EXCLUSIVE OR GATE)

·        4081 (  QUADRUPLE 2- INPUT AND GATE )

·        4071 (QUADRUPLE 2- INPUT OR GATE )

·        4069 (HEX INVERTER)

Connection Of Basic IC's

      Ring Counter

·The counter is adjusted to count 9 clocks by connecting                      a Q₉ pin with the reset pin of the counter.

· We will use the positive edge clock (cp₀) so (cp₁') is                   earthed.

·        The Q₇ and Q₈ of the counter is applied to 2- input OR gate to control the switching gates (AND Gate).

·        The Q₉ pin is connected to the reset of the D flip flop to reset the contents to zero.

Error Simulation

·        Is a logic Gate (EXCLUSIVE OR GATE).

·        The received vector is applied to one input of XOR.

·        Another terminal is connected to dc voltage or earth.

·        If the terminal is connected to earth, then the received vector is correct.

·        If the terminal is connected to dc voltage, then the received vector is incorrect.

·         If a dc voltage is considered as any output of ring counter, then one bit only is errored (inverted).

The Operation Of The Circuit

·        For the first 7 clocks the switching AND gate is switched on.

·        At these 7 clocks the received vector is entered into the D flip flop and the division process is carrying out.

·        After the 7 clocks the switched AND gate is switched off.

·        The division process is carried out and the contents of the D flip flop are the syndrome.

·        At the 8^th clock the syndrome is read by displaying LED's.

·        At the 9^th clock the D flip flop resets to zero.

·        Now the D flip flop is ready to receive a new code vector

·        The same steps are carried out for the new code vector