Title:
TONE DETECTING CIRCUIT
Document Type and Number:
Japanese Patent JPS57176869
Kind Code:
A
Abstract:
Tone detection circuitry including tone decoder providing a free running frequency determined by timing resistance and timing capacitance connected to it. A control means including a programmable microprocessor establishes a retrieval record based on the product of the timing resistance and timing capacitance needed to establish the center frequency of the tone decoder for a plurality of bandwidths. The retrieval record is used to establish the product of the timing resistance and timing capacitance when a tone within the selected bandwidth is to be detected.
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Inventors:
DONARUDO RUIZU NOORERU
Application Number:
JP5362582A
Publication Date:
October 30, 1982
Filing Date:
March 31, 1982
Export Citation:
Assignee:
MINNESOTA MINING & MFG
International Classes:
H04L27/26; G01R23/15; G01R25/00; H04L27/00; (IPC1-7): H04L27/00; H04L27/26