Apparatus for converting an analog c-band broadcast receiver into a system for simultaneously receiving analog and digital c-band broadcast television signals

• US 5,649,318 A
• Filed: 03/24/1995
• Issued: 07/15/1997
• Est. Priority Date: 03/24/1995
• Status: Expired due to Fees

• Current Assignee: Datasec Corporation
• Original Assignee: Terrastar, Inc.
• Inventors: Lusignan, Bruce B.
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Flynn, Nathan J.
• Application Number:
  US08/409,981
• Time in Patent Office: 844 Days
• Field of Search: 348/554, 348/555, 348/705, 348/706, 348/725, 364/919.3, 455/3.2, 455/142, 455/143
• US Class Current: 725/70
• CPC Class Codes: H04B 1/26 for superheterodyne receivers multiple frequency-changing H03D7/16
• CPC Class Codes: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04H 40/90 specially adapted for satellite broadcast receiving
• CPC Class Codes: H04N 7/20 Adaptations for transmission via a GHz frequency band, e.g. via satellite

Abstract

An adapter for a direct broadcast television system enables owners of existing dish antennas to receive both current analog television broadcasts and new digital television broadcasts via C-Band satellites. The adapter includes a coaxial switch for switching between analog and digital television, a tuneable demodulator for selectively switching between transponders on the C-Band satellites, a channel selector unit for selecting the channel specified by the user from the bit stream output by the demodulator, a channel expander for decompressing the video signal, and a control unit for accepting user commands and controlling the polarization of the received signals, the steering of the TVRO antenna, the demodulated transponder frequency and the demultiplexed channel. The ability to select the user'"'"'s channel from multiple channels available on different transponders and different satellites allows the dynamic reassignment of television channels based on system efficiency considerations. The adapter described herein permits a smooth transition from existing television service to a new digital C-Band television service, without requiring a new antenna or removal of the existing antenna. The device is able to simultaneously serve analog and digital TV to both cable and TVRO and C-Band small antennas and enables a smooth, seamless conversion to digital C-Band receivers with only one box. In addition, the system design minimizes satellite costs and equipment conversion costs. Rapid change to 8 channels per transponder for TVRO and cable is then followed by reduction to 3 and 4 channels to permit use of small C-Band antennas without interrupting service to existing customers.

Claims

1. An apparatus for converting an analog C-Band broadcast receiving system into a system for simultaneously receiving analog C-Band broadcast television signals and digital C-Band broadcast television signals, in which the analog C-Band broadcast receiving system includes an antenna, and an analog receiver for converting the received signal to a television ready signal selected by a user, the apparatus being coupled between the antenna and the analog receiver and between the analog receiver and a video device, said apparatus comprising:

a) a control unit having a digital operating mode and an analog operating mode, receiving a mode command from the user for switching the apparatus into either the analog operating mode for receiving the analog C-Band broadcast television signals or into the digital operating mode for receiving the digital C-Band broadcast television signals, receiving a digital channel selection command from the user indicating which digital television channel should be output in the digital operating mode, outputting a digital channel selection signal, and outputting a transponder selection signal;

b) a switch having an input being coupled to the antenna for receiving the signal, having a first output being coupled to said analog receiver, having a second output, having a control input being coupled to the control unit, whereby the control unit controls the switch via the control input so that the received signal is output to the second output in the digital operating mode and the received signal is output to the first output in the analog operating mode;

c) a demodulator being coupled to the second output of the switch, receiving the received signal in the digital operating mode, receiving the transponder selection signal from the control unit, and demodulating a bit sequence from the received signal at a carrier frequency specified by the transponder selection signal;

d) a channel selector receiving the bit sequence from the demodulator, receiving the digital channel selection signal from the control unit, and demultiplexing the bit sequence to form a selected compressed digital television signal;

e) a channel expander receiving the selected compressed digital television channel and decompressing the selected compressed digital television signal to form a selected digital television signal;

f) a digital-to-analog converter receiving the selected digital television signal and converting the selected digital television signal into an analog television-ready signal; and

g) an output coupler being coupled to the video device, receiving the analog television-ready signal from the digital-to analog converter in the digital operating mode, and receiving an additional analog television-ready signal from said analog receiver in the analog operating mode, and outputting the analog television-ready signal from the digital-to analog converter in the digital operating mode and outputting the additional analog television-ready signal in the analog operating mode.

2. The apparatus according to claim 1, wherein the control unit provides a polarization select signal to the antenna to change a polarization of the received signal received by the switch.

3. The apparatus according to claim 1, wherein the channel selector outputs a data management channel to the control unit, which data management channel contains information regarding programs available on all digital television channels on all satellites and transponders transmitting the digital C-Band broadcast television signals.

4. The apparatus according to claim 1, wherein several digital television signals are modulated on each transponder carrier signal using a minimum shift keying modulation technique and the demodulator demodulates the received signal using a minimum shift keying demodulation technique.

5. The apparatus according to claim 1, wherein a first plurality of digital television signals are transmitted by each transponder on each C-Band satellite using a first polarization and a second plurality of digital television signals are transmitted by said each transponder on said each C-Band satellite using a second polarization, and the control unit transmits a polarization select signal to said antenna based on the digital channel selection command received from the user, which polarization select signal determines whether the received signal received by the switch contains the first plurality of digital television signals or the second plurality of digital television signals from the satellite at which the antenna is aimed and from the transponder specified by the control unit via the transponder select signal.

6. The apparatus according to claim 1, wherein a first RF signal containing a first plurality of digital television signals is transmitted by a first C-Band satellite and a second RF signal containing a second plurality of digital television signals is transmitted by a second C-Band satellite, and the control unit transmits a satellite steering control signal to said antenna based on the digital channel selection command received from the user, which satellite steering control signal determines whether the first RF signal or the second RF signal is received by the antenna.

7. The apparatus according to claim 5, wherein each C-Band satellite that is broadcasting digital television channels can dynamically reassign each digital television channels to any transponder on said each C-Band satellite, using any polarization and in any channel location within its multiplexing scheme, and said control unit correspondingly dynamically modifies the polarization selection signal, the digital channel selection signal and the transponder selection signal based on information contained in the data management channel to cause the channel selector unit to output the digital television channel specified by the user via the digital channel selection command.

8. The apparatus according to claim 7, wherein the control unit further comprises a storage unit storing a plurality of default values for each digital television channel available on all satellites and all transponders.

9. The apparatus according to claim 8, wherein the plurality of default values include a satellite indicator, a transponder indicator, a polarization indicator, and a bit frame assignment.

10. The apparatus according to claim 9, wherein the control unit regularly updates the plurality of default values based on information included in the data management channel.

11. The apparatus according to claim 1, wherein the control unit includes a storage unit that stores user specified data sets representing a user organized list of available channels.

12. The apparatus according to claim 1, further comprising a picture combiner having an input coupled to the control unit and an output coupled to the digital-to-analog converter, converting a text message signal output by the control unit into a text overlay signal, overlapping the text overlay signal on the selected digital television channel and outputting the text overlayed television signal to the digital-to-analog converter.

13. The apparatus according to claim 12, wherein the control unit further comprises a storage unit, the control unit outputs a master channel list of all available digital channels based on a user command to do so, which master list is overlayed on the selected digital television channel by the picture combiner, and the control unit creates a subset of the available digital channels based on a series of commands sent by the user and stores this list in the storage in a user named file.

14. The apparatus according to claim 13, wherein the control unit retrieves the user name file and outputs it to the picture combiner upon a command to do so from the user.

15. The apparatus according to claim 1, further comprising:

a) a caption generator being coupled to the control unit, wherein the caption generator receives a text message signal from the control unit and outputs a video text signal representing the text message; and

b) a picture combiner being coupled to the caption generator and the channel expander, receiving the video text signal from the caption generator, receiving the selected digital television signal from the channel expander, and combining the video text signal and the digital television channel into a combined text and video signal.

16. The apparatus according to claim 1, further comprising a display being coupled to the control unit for displaying the selected digital television channel number to a user.

17. A method for receiving both analog C-Band satellite broadcast television signals and digital C-Band satellite broadcast television signals using a single receiving antenna, a device for receiving the analog C-Band satellite broadcast television signals and an adapter module coupled to the receiving antenna and the device, in which a first plurality of digital television channels are multiplexed into a first bit sequence, a second plurality of digital television channels are multiplexed into a second bit sequence, the first bit sequence is modulated on a first carrier signal and transmitted from a first transponder on a particular C-Band satellite using a first polarization, the second bit sequence is modulated on the first carrier signal and transmitted from a first transponder on the particular C-Band satellite using a second polarization, and the first and second bit sequences also include a data management channel specifying a satellite, a carrier frequency, a polarization and a bit frame assignment for all available digital television channels, including digital television channels being transmitted from other C-Band satellites, said method comprising the steps of:

a) switching a mode of the adapter module to either an analog reception mode or a digital reception mode based on a mode reception command from a user;

b) in the analog reception mode, including the steps of;

(i) controlling a switch in the adapter module to couple a received RF signal containing the analog C-Band satellite broadcast television signals from the receiving antenna to the device;

(ii) receiving a television-ready signal from the device; and

(iii) providing the television-ready signal as an output from the adapter module; and

c) in the digital reception mode, including the steps of;

(i) receiving a digital television channel selection command from a user specifying a particular digital television channel to be provided as an output from the adapter module;

(ii) determining a particular carrier frequency, a particular polarization, and a particular bit frame assignment for the particular digital television channel based on information contained in the data management channel;

(iii) controlling the receiving antenna so that the receiving antenna outputs a polarized RF signal having the particular polarization;

(iv) controlling the switch so that an intermediate frequency signal corresponding to the polarized RF signal is coupled to a demodulator;

(v) controlling the demodulator so that the demodulator demodulates the intermediate frequency signal at the particular carrier frequency to form a bit sequence;

(vi) controlling a channel selector so that the channel selector demultiplexes a compressed version of the digital television channel from the bit sequence output by the demodulator based on the particular bit frame assignment;

(vii) restoring the compressed version of the particular digital television channel to the particular digital television channel; and

(viii) converting the particular digital television channel to a television-ready signal.

18. The method according to claim 17, wherein the digital reception mode further comprises the steps of:

(ix) using default values for the particular polarization, the transponder carrier frequency and the bit frame assignment, upon first switching from the analog reception mode to the digital reception mode; and

(x) reading the data management channel using the default values to determine the particular polarization, the particular transponder carrier frequency and the particular bit frame assignment for the particular digital television channel.

19. The method according to claim 17, wherein the digital reception mode further comprises the steps of:

(ix) storing default values for the particular polarization, the transponder carrier frequency and the bit frame assignment in the adapter module;

(x) using the default values for the particular polarization, the transponder carrier frequency and the bit frame assignment, upon first switching from the analog reception mode to the digital reception mode; and

(xi) updating dynamically the default values with information contained in the data management channel as long as the adapter module remains in the digital reception mode.

20. The method according to claim 19, wherein the digital television channels are reassigned dynamically at least among a plurality of C-Band satellite transponders, all available polarizations and all available bit frame assignments, and further comprising the steps of:

(xii) repeating steps c) (iii) and c) (v) through c) (viii) whenever the default values for the particular digital television channel are changed by said updating in step (ix).

21. A converter for coupling to an analog satellite television receiver, which includes an outdoor unit coupled to a satellite antenna and an indoor unit for coupling to a television or other video device, said converter comprising:

a) a coaxial switch having a first input being coupled to the outdoor unit for receiving a polarized intermediate frequency (IF) signal, having a second input being coupled to the indoor unit for receiving a steering control signal, having a third input being coupled to the indoor unit for receiving a polarization select signal, having a fourth input for receiving a second steering control signal, having a fifth input for receiving a second polarization select control signal, having a control input for switching the switch between a first position and a second position, having a first output being coupled to the indoor unit for providing the polarized IF signal to the indoor unit, having a second output being coupled to the outdoor unit for providing the steering control signal to the outdoor unit, having a third output being coupled to the outdoor unit for providing the polarization select signal to the outdoor unit, and having a fourth output for the polarized IF signal, wherein in the first position the coaxial switch couples the first input to the first output, couples the second and third inputs to the second and third outputs, respectively, and in the second position the coaxial switch couples the first input to the fourth output, and couples the fourth and fifth inputs to the second and third outputs, respectively;

b) a tuneable demodulator having a first input being coupled to the fourth output of the coaxial switch for receiving the polarized IF signal, having a second input for receiving a transponder select signal, and providing a bit sequence as an output, which bit sequence was modulated on a carrier frequency using a minimum shift keying modulation technique;

c) a demultiplexer having a first input being coupled to the output of the tuneable demodulator, having a second input for receiving a bit frame assignment for determining which compressed digital television channel within the bit sequence received from the tuneable demodulator is to be output, providing a compressed digital television signal as a first output, and providing a data management channel as a second output, which data management channel contains information necessary to receive all available digital television channels being broadcast from C-Band satellites in a particular viewing region;

d) a video decompressor having an input being coupled to the output of the demultiplexer and providing a restored version of the compressed digital television signal;

e) a digital-to-analog converter having an input being coupled to the video decompressor, converting the restored version of the compressed digital television signal to a video signal and providing the video signal as an output;

f) a splitter having a first input being coupled to the indoor unit for receiving a selected analog television signal, having a second input being coupled to the output of the digital-to-analog converter for receiving the video signal, and having an output for coupling to the television or other video device; and

g) a controller having a first input being coupled to the demultiplexer for receiving the data management channel, having a second input for receiving commands from a user, having a first output being coupled to the fourth input of the coaxial switch for sending the second steering control signal to the coaxial switch, having a second output being coupled to the fifth input of the coaxial switch for sending the second polarization select control signal to the coaxial switch, having a third output being coupled to the control input of the coaxial switch for controlling the position of the coaxial switch, having a fourth output being coupled to the second input of the tuneable demodulator for sending the transponder select signal to the tuneable demodulator, having a fifth output being coupled to the second input of the demultiplexer for sending the bit frame assignment, wherein upon a receipt of a command from the user to output a particular digital television signal, the control unit switches the coaxial switch via the control input to the second position, determines a first value for the steering control signal, a second value for the polarization select signal, a third value for the transponder select signal, and a fourth value for the bit frame assignment based on information contained in the data management channel, and outputs the first, second, third, and fourth values as the first, second, fourth and fifth outputs, respectively.

22. The converter according to claim 21, further comprising a decryptor unit having an input being coupled to the first output of the demultiplexer, and having an output being coupled to the digital-to-analog converter, wherein the compressed digital television signal is in encrypted form, and the decrypter unencrypts the compressed digital television signal and provides the unencrypted compressed digital signal as an output.

23. The converter according to claim 21, further comprising an error correction unit having an input being coupled to the first output of the demultiplexer, and having an output being coupled to the digital-to-analog converter, wherein the error correction unit corrects errors in the compressed digital television signal and provides the corrected compressed digital signal as an output.

24. The converter according to claim 21, further comprising text overlaying device having a first input being coupled to the control unit for receiving text messages from the control unit, having a second input for receiving the restored version of the compressed digital television signal and providing a combined text and video digital television signal as an output to the digital-to-analog converter.

25. A method for converting from analog C-Band television service to digital C-band television service without interrupting service to users, comprising:

a) converting a first transponder on a satellite to digital television service by modulating a first plurality of compressed digital television channels and a data management channel on a first carrier frequency for the first transponder, wherein the data management channel contains information for all channels provided by the digital C-Band television service, which information includes receiver parameters necessary to receive each of the first plurality of compressed digital television channels;

b) switching between analog C-Band television service and digital C-Band television service in an adapter module in response to a service selection signal from a user;

c) receiving a digital television channel selected by the user by modifying a digital receiver according to the receiver parameters for the digital television channel selected by the user contained in the data management channel;

d) converting a second transponder on the satellite to digital television service by modulating a second plurality of compressed digital television signals and said data management channel on a second carrier frequency for the second transponder;

e) updating the information in the data management channel to provide updated receiver parameters necessary to receive each of the compressed digital television channels in the first and second plurality of digital television channels; and

f) modifying the digital receiver according to the updated receiver parameters.

26. The method according to claim 25 further comprising the steps of:

g) moving a subset of the channels in the first plurality of compressed digital television channels to the second plurality of compressed digital television channels while simultaneously performing the step d) of converting.

27. The method according to claim 26, wherein the number of channels in the first and second plurality of compressed digital television channels after step g) of moving is performed is the same as the number of channels in the first plurality of compressed digital television signals before the steps g) and d) are performed.

28. The method according to claim 25, further comprising the steps of:

g) simultaneously reducing the number of channels in the first plurality of compressed digital television channels while increasing the number of transponders converted according to step d) of converting so that the total number of compressed digital television signals provided by the digital television service never decreases.

29. The method according to claim 28, wherein steps e) and f) are continuously performed so that user intervention is not required when step g) is performed.

30. An adapter for coupling to a TVRO antenna and an indoor unit of a C-band satellite broadcast receiving system to allow reception of both analog C-band television programming, and digital C-band television programming, said adapter comprising:

a) means for switching between a first mode for receiving the analog C-band television programming and a second mode for receiving the digital C-Band television programming;

b) means for passing the analog C-band television programming to the indoor unit in the first mode;

c) means for receiving the digital C-band television programming in the second mode; and

d) means for controlling the switching means and the receiving means based on a viewer preference.

31. An apparatus for converting an analog C-band receiver into an analog and digital C-band receiver, comprising:

a) a first input for receiving a television signal containing with either an analog signal or a digital signal;

b) a second input for receiving a viewer channel selection signal indicating whether a viewer has selected a digital television channel or an analog television channel;

c) a first output for outputting the television signal when the viewer channel selection signal indicates the viewer has selected an analog television channel, said first output for coupling to said analog C-band receiver;

d) a second output for outputting a television-ready signal, said second output for coupling to a video device;

e) a third input for receiving a television-ready signal from the analog C-band receiver;

f) a digital C-band receiver converting the digital signal into a second television-ready signal and outputting a second television-ready signal to the second output when the viewer channel selection signal indicates the viewer has selected a digital television channel, wherein said second output outputs either the first or second television-ready signal depending on whether the viewer has selected an analog or digital television channel, respectively.