Hybrid analog/digital television transmission system

• US 5,532,748 A
• Filed: 03/31/1995
• Issued: 07/02/1996
• Est. Priority Date: 03/31/1995
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation Of North America (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Corporation Of America (Panasonic Holdings Corporation)
• Inventors: Naimpally, Saiprasad V.
• Primary Examiner(s): Metjahic, Safet
• Application Number:
  US08/414,334
• Time in Patent Office: 459 Days
• Field of Search: 348/385-389, 348/432, 348/437, 348/438, 348/426, 348/469, 348/470, 348/473, 348/487, 348/554-556, 348/725, 348/558, 348/614, 375/260, 370/76, 370/69.1
• US Class Current: 375/240.25
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/42638 involving a hybrid front-end, e.g. analog and digital tuners
• CPC Class Codes: H04N 21/4384 involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
• CPC Class Codes: H04N 5/211 Ghost signal cancellation H04N23/81 takes precedence
• CPC Class Codes: H04N 7/08 Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band , e.g. by time division H04N7/007 takes precedence

Abstract

A system and method for providing a video signal during the delay time between when a new channel is selected and when the digital picture is acquired and displayed is disclosed. In particular, the system provides an NTSC-like analog video signal along with a conventional digital television signal such that when a user initially makes a new channel selection, the analog video signal, which can be quickly and easily decoded, is presented for display until the digital television signal is completely decoded and acquired. As soon as the digital television signal is ready for display, the displayed signal switches from the analog video signal to the digital television signal. For purposes of conserving frequency spectrum, the analog video signal is a simple NTSC-like monochrome (i.e., black and white) signal and limited to a 1 MHz band of the available 6 MHz spectrum allocated for each channel.

Claims

1. An encoding/transmission system for providing a video signal to occupy a delay time defined from when a user selects a new channel to when a digital video signal is decoded, acquired and displayed comprising:

means for receiving a signal representative of a video signal and for Converting said signal representative of a video signal into a digital video signal occupying a first predetermined band of frequencies;

means for receiving the signal representative of the video signal and for providing an analog video signal therefrom, said analog video signal occupying a second predetermined band of frequencies exclusive of the first band of frequencies; and

means for combining the analog video signal with the digital video signal, wherein the analog and digital video are spectrally separate, to produce a hybrid video signal suitable for transmission within a conventional single channel frequency spectrum allocation.

2. The encoding/transmission system of claim 1, wherein the first predetermined band of frequencies has approximately a 5 MHz bandwidth.

3. The encoding/transmission system of claim 1, wherein the second predetermined band of frequencies has approximately a 1 MHz bandwidth.

4. An encoding/transmission method for providing a video signal to occupy a delay time defined from when a user selects a new channel to when a digital video signal is decoded, acquired and displayed comprising the steps of:

receiving a signal representative of a video signal and converting said signal representative of a video signal into a digital video signal occupying a first predetermined band of frequencies;

receiving the signal representative of the video signal and providing an analog video signal therefrom, said analog video signal occupying a second predetermined band of frequencies spectrally separate from the first predetermined band; and

combining the analog video signal to the digital video signal to produce a hybrid video signal suitable for transmission within a conventional single channel frequency spectrum allocation.

5. The encoding/transmission method of claim 4, wherein the first predetermined band of frequencies has approximately a 5 MHz bandwidth.

6. The encoding/transmission method of claim 4, wherein the second predetermined band of frequencies has approximately a 1 MHz bandwidth.

7. A receiving/decoding system for providing a video signal to occupy a delay time defined from when a user selects a new channel to when a digital video signal is decoded, acquired and displayed comprising:

means for receiving and decoding the digital video signal transmitted in a first predetermined band of frequencies;

means for receiving and decoding an analog video signal transmitted in a second predetermined band of frequencies;

means for detecting a new channel selection and, depending on a decoding status of the digital video signal for the newly selected channel, producing a control signal; and

means, responsive to the control signal, for selecting either the analog video signal or the digital video signal to be displayed.

8. The receiving/decoding system of claim 7, wherein the first predetermined band of frequencies has approximately a 1 MHz bandwidth.

9. The receiving/decoding system of claim 7, wherein the second predetermined band of frequencies has approximately a 5 MHz bandwidth.

10. The receiving/decoding system of claim 7, wherein the means for selecting is a switching circuit.

11. The receiving/decoding system of claim 7, wherein the means for receiving and decoding an analog video signal includes a ghost cancellation means for providing ghost cancellation information to the means for receiving and decoding the digital video signal.

12. A receiving/decoding method for providing a video signal to occupy a delay time defined from when a user selects a new channel to when a digital video signal is decoded, acquired and displayed comprising the steps of:

providing the digital video signal and a analog signal together in a conventional single channel frequency spectrum allocation;

receiving and decoding the digital video signal transmitted in a first predetermined band of frequencies within the single channel allocation;

receiving and decoding the analog video signal transmitted in a second predetermined band of frequencies within the single channel allocation;

detecting a newly selected channel and, depending on a decoding status of the digital video signal for the newly selected channel, producing a control signal; and

selecting, in response to the control channel, either the analog video signal or the digital video signal to be displayed.

13. The receiving/decoding method of claim 12, wherein the first predetermined band of frequencies has approximately a 1 MHz bandwidth.

14. The receiving/decoding method of claim 12, wherein the second predetermined band of frequencies has approximately a 5 MHz bandwidth.

15. A system for providing a video signal to occupy a delay time defined from when a user selects a new channel to when a digital video signal is decoded, acquired and displayed comprising:

an encoding/transmission means including;

means for providing the digital video signal in a first predetermined band of frequencies;

means for providing an analog video signal in a second predetermined band of frequencies exclusive of the first predetermined band; and

means for combining the analog video signal to the digital television signal to produce a hybrid video signal suitable for transmission within a conventional single channel frequency spectrum allocation;

a receiving/decoding means including;

means for receiving and decoding the digital video signal;

means for receiving and decoding the analog video signal;

means for detecting a newly selected channel and, depending on a decoding status of the digital video signal for the newly selected channel, producing a control signal; and

means, responsive to the control signal, for selecting either the analog video signal or the digital video signal to be displayed.

16. The system of claim 15, wherein the first predetermined band of frequencies has approximately a 1 MHz bandwidth.

17. The system of claim 15, wherein the second predetermined band of frequencies has approximately a 5 MHz bandwidth.

18. The system of claim 15, wherein the means for selecting is a switching circuit.

19. The system of claim 15, wherein the means for receiving and decoding an analog video signal includes a ghost cancellation means for providing ghost cancellation information to the means for receiving and decoding the digital video signal.

20. The system of claim 15, wherein the analog video signal is a monochrome signal.