PURPOSE: To automatically detect discrepancies among plural framing codes, by serial-parallel converting framing codes from repeatedly transmitted information and detecting coincidence of the framing codes from the converted output.
CONSTITUTION: A serial data signal (a) inputted into a terminal 12 is converted into a parallel signal by means of a clock signal (b) at a seral-parallel circuit 1 and the output is impressed upon a coincidence detecting circuit 2. The output (d) of the circuit 2 becomes a coincident pulse of a high level only when the output (d) coincides with any one of framing codes FC A, B, and C, and outputs (e), (f), and (g) of the circuit become pulses for generating high-level coincident pulses having error correcting capabilities, only when they coincide with the framing codes FC A, B, and C, respectively. FFs 5∼7 are reset by a selection start signal (c) from a terminal 13 and a high-level pulse (e) is latched at the FF5. The combination of a reset circuit 3 and AND gate 4 generates a coincident pulse extracting pulse (i) from the signals (d) and (c) and releases the latched condition of the FF5, and then, outputs an FC signal (k) to the coincident FC A from an AND gate 8.
SUGINO NOBUO
SAEKI HIROAKI
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