Abstract:
An in-line digital cable television adapter and method for receiving and converting digital television signals to an analog format for display on an analog television set. Dual-capable video decryption and decoding is available to support a television, VCR, and a picture-in-picture independently and simultaneously. Dual-BTSC audio and video frequency modulators are available for output. A bypass switch selectively switches between television channels for modulation and for passing an analog supplied television signal directly to the analog television set. An infrared transceiver integrated with the digital cable adapter receives infrared frequencies from a compatible infrared remote control and stimulates input to a target infrared receiver.

Description:
REFERENCE TO RELATED APPLICATION  
       [0001]     The present application claims the benefit of U.S. Provisional Patent Application No. 60/472,413, filed on May 22, 2003, and U.S. Provisional Patent Application No. 60/475,001, filed on Jun. 3, 2003, whose disclosures are hereby incorporated by reference in their entireties into the present disclosure. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention is generally related to digital cable television, and, more particularly, is related to an apparatus and method for viewing digital cable television on a conventional analog television set.  
       DESCRIPTION OF RELATED ART  
       [0003]     Analog television will be phased out by 2006 in favor of digital television, which has advantages such as a greater number of channels in a given bandwidth. There is thus a need to provide consumers with a transition from analog to all-digital broadcasting.  
         [0004]     However, analog television set consumers will most likely resent having to buy new equipment within a narrow time window to take advantage of digital television. Also, in a switch-over solution, to enjoy wide acceptance, the solution must take into account the existence of video cassette recorders and picture-in-picture televisions. Furthermore, a television with such capabilities built in requires that the user purchase a new television set.  
         [0005]     Another difficulty with traditional cable television set-top boxes is their radial design, i.e., all connections are on the same surface of the set-top box. That design imposes limitations on the placement of the set-top box. Thus, a heretofor unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.  
       SUMMARY OF THE INVENTION  
       [0006]     Embodiments of the present invention provide an in-line digital cable adapter (DCA) and method for allowing digital cable television signals to be viewed on a conventional analog television set. The adapter includes a 3/4/Analog-bypass switch. The switch allows the output to be sent to channel 3 or 4, as is known in the art, and also adds a novel feature in that if the input is analog, the digital to analog conversion can be bypassed, so that the input and output are both analog. Thus, when the time comes to switch from analog to digital inputs, the customer can simply flip the switch accordingly.  
         [0007]     This invention allows an MSO to deploy the DCA to all of its analog cell subscribers and have them run in analog bypass mode. The MSO would then identify its subscribers of the “Digital Cutover Date” on which the subscribers would switch to digital mode. The converted programming output will be compatible with analog televisions and VCR&#39;s using channel 3 or 4 modulation. Alternatively, the switch can be software-controlled, and the MSO can send a signal to actuate the switch.  
         [0008]     In one embodiment, the claimed invention provides a secondary path for independent VCR support with integrated use of a single infrared (IR) transceiver. This is important to the successful transition to all digital networks due to the number of VCRs coupled with televisions and the requirement to offer an exact substitution for the functionality that analog consumers have with analog cable television and their TVs and VCRs.  
         [0009]     The mechanical utility of the coaxial/in-line application of the digital cable adapter is that its design is in-line with the coaxial cable that provides the cable television source. This allows flexibility to the connection to the television and VCR, the cable wall outlet, and a needed alternating current (AC) power outlet. To accomplish this advantage, the infrared transceiver either is integrated in the structure of the digital cable adapter or can be designed as a tethered attachment. The infrared transceiver is located near the front or ‘faces’ of the television and VCR for exposure to a compatible infrared remote control. The infrared transceiver simulates the VCR infrared input. The infrared transceiver can also be replaced with any other suitable technology, such as a radio frequency (RF) transceiver.  
         [0010]     In other embodiments of the claimed invention, the following features may be included:  
         [0011]     dual-capable video decryption and decoding to support a TV and VCR or picture-in-picture (PIP) independently and simultaneously;  
         [0012]     dual-BTSC Audio and RF modulators;  
         [0013]     TV/VCR relationship for integration of the dual path technology described above;  
         [0014]     a graphical user interface (GUI) for VCR control (this can be based on existing GUIs for VCR control, which are well known in the art and therefore will not be disclosed in detail here, however, their use in the context of the claimed invention is novel);  
         [0015]     an infrared transceiver for receiving remote control commands from a remote control while simultaneously providing control to the VCR unit; and  
         [0016]     the ability to select the modulation channel (3 or 4, and so forth) for digital mode or analog bypass.  
         [0017]     Other systems, methods, features, and advantages of the present invention will be or become apparent to one skilled in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     A preferred embodiment of the present invention and variations thereof will be set forth in detail with reference to the drawings, in which:  
         [0019]      FIG. 1  is a functional block diagram of an embodiment of the digital cable adapter;  
         [0020]      FIGS. 2A and 2B  are reduced fit block diagrams of modifications of the digital cable adapter of  FIG. 1  where the outputs have been reduced to 2 and 1 RF modulated outputs, respectively;  
         [0021]      FIGS. 3A and 3B  illustrate a proposed layout arrangement of components in the digital cable adapter of  FIG. 1 ;  
         [0022]      FIGS. 4A-4D  illustrate perspective drawings of an assembly of the digital cable adapter of  FIG. 1 ; and  
         [0023]      FIG. 5  is a perspective drawing of an embodiment of the invention with a removable circuitry component.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]     A preferred embodiment of the invention and modifications thereof will now be described with reference to the drawings, in which like reference numerals refer to like elements throughout.  
         [0025]      FIG. 1  illustrates a functional block diagram of the DCA. In practice, some of the components may or may not be fitted for use.  
         [0026]     In this disclosure and the drawings, it will be understood that disclosures of specific standards, protocols, and the like are illustrative rather than limiting. For example, while the disclosed preferred embodiments may use quadrature amplitude modulation (QAM), MPEG decoding, and the like, the invention as broadly defined uses a modulation technique such as QAM, a decoding technique such as MPEG, etc. Of course, if the digital cable adapter is manufactured for use outside the United States, the standards appropriate for the country of intended use are used.  
         [0027]     The DCA  100  is connected to the Cable TV source  106  through which either analog or digital television signals  104  are delivered to an input  102 . If the network still delivers analog services, a switch  118  (3/4/Analog-bypass switch) is set to Analog-bypass, and the DCA  100  will act as a splitter/impedance matching circuit and pass the analog television signals through to the TV and VCR outputs (for connection to suitable display, recording, or other devices). Once the network delivers only digital services, the switch  118  is set to either channel 3 or 4 for modulated operation. A first circuitry  108  converts the digital television signals to an analog format for output to analog TVs and VCRs. In a Fully-Featured DCA, base band outputs could be available so that un-modulated video and audio can be provided to base band inputs of TVs and VCRs.  
         [0028]     Using a companion remote control with a TV/VCR (or A/B) switch, the user selects which of the two paths is being controlled (TV or VCR, A or B, etc.) and selects the channel to be QAM demodulated and MPEG decoded for output via the RF or base band outputs. It should be noted that a DCA  100  can be envisioned that has more than two channel capability.  
         [0029]     Memory, such as programmable memory  136  (one-time programmable or reprogrammable), provides for security information (keys/certificates) to be programmed into the DCA  100  during manufacture, or in the field to enable a conditional access scheme once the DCA  100  is deployed on a network. The addition of small form-factor security cards (e.g., SIM format) would also enable content protection. In order to allow control of a VCR, a graphical user interface (GUI) (not shown) is provided which will give the user the ability to schedule the recording of a program on a VCR connected to the DCA  100 ; for example, by setting Start, Stop, Date, and Channel information. The graphical user interface (not shown) will also allow for other user information, for example channel number and call letters, time of day, etc.  
         [0030]     To receive infrared (IR) control signals  128  from a remote control (not shown) and to transmit IR control sequences to the VCR, an IR Transceiver  126  is defined. The IR Transceiver  126  will transmit commands such as a Record and Stop command pair to the VCR&#39;s IR input at the appropriate Start and Stop times, respectively. This IR Transceiver  126  can be removably attached via a tether wire (not shown) and plug/jack pair (not shown) or integrated into the unit. Multiple conductors will be employed on the IR connector jack to allow a (serial) data interface (not shown) to the sealed production unit for test, diagnostics, and upgrades using a special service cable.  
         [0031]     The reduced-fit version  200 A or  200 B of the DCA shown in  FIG. 2A  or  2 B is the likely deployed embodiment where the outputs have been reduced to first and second RF modulated outputs  112 ,  114 , respectively, or to a single RF modulated output  212 . Any modification to the DCA  100  taught in the present specification may be made to the DCA  200 A or  200 B, insofar as is technologically feasible. A fuller explanation of the single output  212  will be given below.  
         [0032]     In other embodiments of the DCA  100 ,  200 A or  200 B as actually implemented, variations of silicon integration are possible. For example, tuners may not be in the integrated chip (IC)  144 ,  244 A, or  244 B. Also, the IR Transceiver functionality may be integrated in the housing of the DCA  100 ,  200 A or  200 B via PCB-mounted components with openings/lenses provided instead of the tether wire concept.  
         [0033]      FIGS. 3A and 3B  show a layout of components in the DCA  100 : Indicated is a four layer circuit board, but any number of layers may be employed as required to accomplish a small form factor.  FIGS. 4A-4D  show perspective views of the assembly of the housing of the DCA  100 .  FIG. 5  shows a modification  500  in which the circuitry  526  for supplying the signal to the VCR is removably attached, both electrically and mechanically, to the rest of the DCA.  
         [0034]     The DCA may be provided as a microprocessor chip  144  ( FIG. 1 ),  244 A ( FIG. 2A ), or  244 B ( FIG. 2B ) with integrated circuits that can support PIP as they provide for two or more tuner paths. Many TVs with 2-tuner PIP will only have one RF input with an internal splitter for feeding its internal tuners. However, one will not be able to connect both RF outputs of the DCA  100  to the one input of a 2-tuner PIP TV. To address that issue, a modification provides for an RF output stage that can set one internal path to one channel (e.g., Channel 3) and the second internal path to another channel (e.g., Channel 4) and combine the two for output to one RF connector. Therefore, the one connector carries both channels 3 and 4. This allows the RF output to go into the RF input of a 2-tuner PIP TV, in which one tuner is set to channel 3 and the other, to channel 4. Now, the DCA  100  can provide PIP for 2-tuner PIP TVs. Since in many television markets, either channel 3 or channel 4 is assigned, another channel, such as channel 5, can be provided for selection by the customer. Any two channels can be used.  
         [0035]     The DCA  200 B of  FIG. 2B  accomplishes the above using the same configuration as in  FIG. 2A , except with only one RF output  212  instead of the two shown in  FIG. 2A . The one RF output  212  can be achieved through industry-known techniques for signal combining, either on chip (preferred) or in a separate circuit.  
         [0036]     This also allows for one cable to route from the DCA  100  to the VCR to the TV as well, where the VCR can be set to channel 4 and the TV can be set to channel 3, thus eliminating the cost of the second RF connector and simplifying the cabling.  
         [0037]     While preferred embodiments of the present invention have been set forth in detail above, those skilled in the art who have reviewed the present disclosure will readily appreciate that other embodiments can be realized within the scope of the present invention. For example, as noted above, QAM, MPEG and the like can be replaced with other technologies. Also, numerical values are illustrative rather than limiting, as is the shape of the device shown in  FIGS. 4A-4D . Furthermore, while the preferred embodiments show two parallel conversion paths for the TV and the VCR or PIP, a device may implement a single conversion path Oust for the TV) or more than two conversion paths (for the TV, VCR and PIP or for additional components). All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.