# US 5,638,112 A · Hybrid analog/digital STB > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,638,112 A - Document ID: US5638112A - Status: Granted - Kind: A - Application number: 08/511,336 - Filed: 1995-08-07 - Granted: 1997-06-10 - Earliest claimed: 1995-08-07 - Assignees: Zenith Electronics Corporation - Inventors: Caitlin B. Bestler; Khosro M. Rabii - Web page: https://patentgrep.com/patent/US5638112A ## CPC - H04N 5/46: for receiving on more than one standard at will (deflecting circuits of multi-standard receivers H04N3/27) - H04N 21/426: Internal components of the client {; Characteristics thereof} (H04N5/44 takes precedence) - H04N 21/42638: {involving a hybrid front-end, e.g. analog and digital tuners} - H04N 21/434: Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream {(demultiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00)} - H04N 5/445: for displaying additional information (H04N5/50 takes precedence) - H04N 5/602: {for digital sound signals} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A hybrid analog/digital STB includes a tuner supplying respective analog and digital television signal processing paths. The analog processing path provides demodulated composite analog video and audio signals and the digital processing path provides demodulated component digital video and audio signals. The demodulated analog and video signals are combined in composite or component form to achieve various desirable effects in a highly flexible system architecture. OSD and display map normalization functions are also integrated within the system architecture. ## Claims ### Claim 1 Apparatus for processing analog and digital television signals received over respective television channels, comprising: a tuner (14) selectively operable for tuning said television channels; an analog processing path (24-28) coupled to the output of said tuner (14) and responsive to a tuned analog television signal for providing a demodulated baseband analog television signal including a first analog composite video signal and a first analog composite audio signal; a digital processing path (32-36, 40) coupled to the output of said tuner (14) and responsive to a tuned digital television signal for providing a demodulated digital television signal including a first digital component video signal and a first digital component audio signal; means (76, 80) for converting the first digital component video signal to a corresponding second analog composite video signal; and first means (82) for linearly mixing said first and second analog composite video signals in selected proportions for providing an output analog composite video signal. ### Claim 2 (depends on 1) The apparatus of claim 1 including an OSD signal generator (66) for providing a digital OSD component video signal and second means (60) coupled between the digital processing path and the OSD generator on the one hand and the means for converting on the other hand for linearly mixing said first and OSD digital video component signals in selected proportions. ### Claim 3 (depends on 2) The apparatus of claim 2 wherein said first and second linear mixing means are both operable in a switch mode. ### Claim 4 (depends on 2) The apparatus of claim 2 wherein said second linear mixing means comprises a first multiplier (62) for multiplying said first digital component video signal by a programmable factor K, a second multiplier (68) for multiplying said digital OSD component video signal by the factor (1-K) and means (64) for combining the outputs of said first and second multipliers. ### Claim 5 (depends on 2) The apparatus of claim 2 including means (72, 74) for converting the first analog composite video signal to a corresponding second digital component video signal and display map normalization means (70) for coupling said first and/or second digital component video signals to said first digital component video signal converting means (76, 80). ### Claim 6 (depends on 1) The apparatus of claim 1 including means (46) for converting the first analog composite audio signal to a corresponding analog component audio signal, means (42) for converting the first digital component audio signal to a corresponding second analog component audio signal and third means (48) for linearly mixing said first and second analog component audio signals in selected proportions for providing an output analog component audio signal. ### Claim 7 (depends on 6) The apparatus of claim 6 including means for selectively adjusting a selected characteristic of said output analog component audio signal. ### Claim 8 (depends on 7) The apparatus of claim 7 wherein said third linear mixing means is operable in a switch mode. ### Claim 9 (depends on 6) The apparatus of claim 6 including means (52) for converting the second analog component audio signal to a corresponding second analog composite audio signal and switch means (54) for coupling a selected one of said first and second analog composite audio signal to an output terminal. ### Claim 10 (depends on 9) The apparatus of claim 9 wherein said means for converting said second analog component audio signal comprises a summer. ### Claim 11 (depends on 9) The apparatus of claim 9 wherein said means for converting said second analog component audio signal comprises a composite audio encoder. ### Claim 12 (depends on 9) The apparatus of claim 9 wherein said switch means comprises means for adjusting a selected characteristic of the selected signal.