# US 4,398,219 A · Switching apparatus for the recording and reproducing of PCM or video signals > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,398,219 A - Document ID: US4398219A - Status: Granted - Kind: A - Application number: 06/316,919 - Filed: 1981-10-30 - Granted: 1983-08-09 - Earliest claimed: 1980-11-06 - Assignees: Sony Corporation - Inventors: Nobuyuki Yasuda - Web page: https://patentgrep.com/patent/US4398219A ## CPC - H04N 9/8205: {involving the multiplexing of an additional signal and the colour video signal} - G11B 20/00007: {Time or data compression or expansion (audio compression based on psychoacoustics G10L19/00; data processing for reproducing audio data at different playback speeds G10L21/04; video compression H04N19/00; data compression per se H03M7/30)} - G11B 20/10527: {Audio or video recording; Data buffering arrangements (G11B20/12 - G11B20/18 take precedence)} - H04N 5/94: Signal drop-out compensation - H04N 9/802: involving processing of the sound signal (H04N9/806, H04N9/835 take precedence) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract A switching apparatus for PCM or video signals is disclosed which includes a circuit detecting the information inherent to a PCM signal and discriminating whether the signal recorded on a record medium is the PCM signal or video signal and a circuit automatically switching the PCM signal and the video signal. ## Claims ### Claim 1 A switching apparatus for PCM or video signals, comprising: (a) an input terminal supplied with a PCM signal or a video signal; (b) an output terminal; (c) a first means coupled to said input terminal for compensating a drop-out contained in said video signal when said video signal is supplied to said input terminal; (d) a second means coupled to said input terminal for detecting a specific information signal contained in said PCM signal when said PCM signal is supplied to said input terminal; and (e) a third means coupled to said second means for switching so as to derive said PCM signal from said input terminal to said output terminal without through said first means in response to an output of said second means. ### Claim 2 (depends on 1) A switching apparatus as claimed in claim 1, wherein said specific information signal contained in the PCM signal is a signal which has a specific frequency and is previously inserted into the PCM signal and said third second means is a filter circuit which extracts the signal of the specific frequency. ### Claim 3 (depends on 1) A switching apparatus as claimed in claim 1, wherein said specific information signal contained in the PCM signal is a frequency component inherent to the PCM signal and said second means is a filter circuit which extracts said inherent frequency component. ### Claim 4 (depends on 1) A switching apparatus as claimed in claim 1, wherein said specific information signal contained in the PCM signal is a white reference signal contained in the PCM signal and said second means is a circuit extracting said white reference signal. ### Claim 5 (depends on 1) A switching apparatus as claimed in claim 1, further comprising: (A) a fourth means connected in series to said first and third means for reducing noise contained in the video signal; and (B) a fifth means coupled to said third means for delivering the PCM signal to said output terminal without passing through said fourth means by the output from said second means when the PCM signal is supplied to said input terminal. ### Claim 6 (depends on 5) A switching apparatus as claimed in claim 5, wherein said third or fifth means is always connected to said first or fourth means respectively and said input and output terminals are connected directly by said third and fifth means. ### Claim 7 (depends on 1, 5) A switching apparatus as claimed in claim 1 or 5 further comprising: (C) a gate circuit connected between said second means and said input terminal, said gate circuit being operated by a pulse corresponding to one horizontal synchronizing signal period formed in said PCM signal to thereby pass therethrough said PCM signal by a predetermined period of time.