GB1065866A - A signal converting system for start-stop telegraph signals - Google Patents

Abstract

1,065,866. Telegraphy. KOKUSAI DENSHIN DENWA KABUSHIKI KAISHA. May 20, 1964 [May 21, 1963; Sept. 11, 1963], No. 20846/64. Heading H4P. In a speed-changing telegraph unit input Start/Stop signals are converted to isochronous signals having a higher bit rate, any gap in the output, due to its higher speed, being filled by a like bit to that last transmitted. In one embodiment, 7¢-bit signals are shaped at 2 and sampled at 3, the samples being stored successively on toggles 4, 5. Unit 24 starts producing sampling pulses at the input bit rate when the output of the shaper 2 is opposite to the bit stored at 4 (i.e. a Start pulse has arrived subsequent to a Stop pulse) and when counter 26 is at rest. Counter 26 counts 7 sampling pulses and allows only these 7 pulses to pass to sampling gates 22a, 22b. Unit 7 provides read-out pulses at the output bit-rate and unit 6 controls the transfer of bits from store 4 to store 5. If one pulse from unit 7 occurs between adjacent sampling pulses from unit 24, store 5 takes up the state of store 4 and the original state of store 5 passes to the output 80. However, if two pulses from 7 occur between adjacent pulses from 24 there is no such transfer of bits in response to the second of these pulses and the bit stored at 5 is repeated to the output. In this manner, whenever the output isochronous signals " overtake " the input signals a Stop bit is inserted between the Stop and Start bits of adjacent characters. Where the output speed is much greater than the input speed more than two stores are used. A multiplex system uses devices as above for each input and time shares the read-out pulses from a common unit 7.