Abstract:
Apparatus and methods are disclosed to store and transmit HDTV signals. The apparatus includes hard disk drives and DVD drives utilized to store HDTV signals and hardware and software to provide constant data feed of HDTV signals into a closed circuit where those signals may be utilized for demonstration purposes of televisions available in a retail store or may be utilized to service HDTV monitors.

Description:
This invention relates to apparatus and methods for receiving and storing and sending HDTV (high definition television) signals and, more particularly, to an apparatus and method for storing and transmitting those signals to display televisions in retail store outlets and to HDTV monitors for servicing same. This application is a continuation-in-part of a provisional application, Ser. No. 60/152,738 filed Sep. 8, 1999 
    
    
     BACKGROUND OF THE INVENTION 
     The change from analog electronic circuitry to digital electronic circuitry in the consumer electronics industry has brought about wide spread change in the products utilized by consumers. Examples of this change can be seen in personal computer and digital telephone circuitry. In the personal computer field, data storage apparatus in the form of hard disk drives and DVD (digital versatile disks) drives have allowed consumers to store massive amounts of digital data and have the ability to send that data to various display apparatus. The use of digital electronic technology has also enabled the advent of high definition television (HDTV) which will provide televisions with better picture quality, better viewing aspect ratio, and larger viewing screens. 
     With the advent of new ATSC digital television standards, manufacturers have begun producing high definition televisions. At this time, a large segment of the broadcast industry has not implemented these new standards. This leaves the manufacturers of HDTV televisions with no economical means of demonstrating their products for sale. 
     Since no off-the-air or cable signals are available in a large part of the world, the manufacturers of HDTV(s) need a device that is capable of supplying an HDTV compatible output. This need can be filled with a player that includes large capacity disk storage devices and advanced video compression algorithms in a device which acts similarly to a known player such as video cassette recorder. 
     As in the video cassette recorder or player, there must be some media for storing the video programming. With HDTV, all of the video and audio information is digital. This new HDTV player utilizes either a hard disk drive or a DVD drive as the media for storing the audio and video content of the HDTV programming. In order to use the hard disk drive or DVD drive for the storage media, a method for retrieving the video data and converting it to 8-VSB (vestigial side band) signal must be developed, as 8-VSB is the modulation format used to transmit HDTV signals. 
     A need has arisen to provide an inexpensive means of demonstrating HDTVs at least until television broadcast stations are running HDTV broadcast signals. 
     Additionally, a need has developed to provide means for storing 8-VSB signals to allow those signals to be used to service HDTV monitors. 
     It is an objective of the present invention, generally stated, to provide a player for storing and sending HDTV format signals in a closed circuit to HDTVS. 
     More particularly, it is a further objective of the present invention to provide an HDTV player utilizing a hard disc drive, or a DVD drive, for storing and retrieving video data and converting it to 8-VSB format for use in a closed circuit to demonstrate and/or service HDTVs 
     SUMMARY OF THE INVENTION 
     The invention resides in a high definition TV player capable of utilizing at least one of a hard disk drive and a DVD drive as the media for storing the audio and video content of HDTV programming. In order to utilize the hard disk drive or the DVD drive for the storage media, video data must be storable therein, and retrieved by the player which converts it to the 8-VSB modulation format used to provide signals to HDTVs. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings wherein like reference numerals identify like elements throughout, and in which: 
     FIG. 1 is a diagrammatic view of the data storage and transmission unit of the present invention shown sending an HDTV compatible signal through a closed circuit to televisions on display in a retail store; 
     FIG. 2 is a block diagram of a first embodiment of the present invention; 
     FIG. 3 is a block diagram of a second embodiment of the present invention; and 
     FIG. 4 is a data transfer block diagram for the second embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a diagrammatic view of a retail appliance store is shown generally at  10 , and it includes a plurality of television sets  11 - 11  which may be viewed by customers  12  and demonstrated by a salesman  13 . In this embodiment, each of the televisions  11  is sent a signal in a closed circuit  14  from the present invention, generally indicated at  15 , shown in block diagram, and identified as a television station in a box. The present invention  15  includes apparatus for storing program material  16 . Apparatus  16  may be a hard disk drive a DVD disk drive or the like. Data containing the audio and digital signal is placed in this medium. This is the stored program material. This data is retrieved from the storage medium  16  and modulated to a base band signal by the modulator  17 . The radio frequency up-converter  18  converts this base-band signal to an RF (radio frequency) signal. Finally, the RF signal is amplified and sent to the output by the output amplifier  19 . This RF signal is then connected to an HDTV  11 - 11  where it is demodulated, decoded, and displayed. 
     Referring to FIG. 2, a more detailed block diagram of the data storage and transmitting operation of the first embodiment is generally indicated at  21 . In this embodiment, this device may be called an HDTV player  21 . The audio and video information is stored on the hard drive  22 , which may be either a hard-disk drive as utilized in present personal computers, or a digital versatile disk drive which may also be used in computers or to show movies on a present generation television. This information is retrieved from the hard drive  22  by the CPU  23  (central processing unit) and stored in two 2-megabyte blocks on the system memory  24 . The bus master controller  25  controls the flow of data from the system memory  24 , through the bus master  26  to the FIFOs (first-in, first-out registers)  27 . The bus master  26 , under control of the bus master controller  25 , copies 1K byte blocks from one of the 2-megabyte blocks in the system memory  24  into the FIFOs  27 . After the block of data is copied to the FIFOs  27 , the bus master  26  reads data from the other 2-megabyte block in the system memory  24 . While the bus master  26  reads from the second block of system memory  24 , the CPU  23  reads more data from the hard disk drive  22  and fills the first block of data in system memory  24 . 
     After reading from one block of data in system memory  24  while the other is being filled, a constant flow of data is maintained into the FIFOs  27 . This provides the 8-VSB modulator  28  of a constant flow of data from the FIFOs  27 . The 8-VSB modulator  28  encodes the data, then converts the incoming data into one of eight voltage levels. This is the base band signal that is used to modulate the radio frequency carrier. This signal can be connected directly to a high definition television  11 . The HDTV demodulates and converts the 8-VSB signal into audio and video. 
     Referring to FIG. 3, a second embodiment of the television station in a box is generally indicated at  31 . Compressed video and audio information in this embodiment is stored on a hard drive  32 , which similarly to the hard drive  22  of the first embodiment may be a hard disk drive or a digital video disk. Compressed digital video and audio information is stored on the hard drive  32  in either the MPEG compressed format or in a pre-encoded format. The pre-encoded format includes proprietary pre-processing of the MPEG data to ease the requirements of the 8-VSB modulator (not shown) and provides a level of copy protection to the system. 
     One of the main requirements of the data transfer is to re-clock the output data at a fixed rate required by the parallel interface and the modulation standard. Data retrieved from the hard drive  32  is not presented at a fixed rate. The transfer of data from the hard drive  32  to the system memory  33  is controlled by the computer&#39;s microprocessor  34  and is continually interrupted as the microprocessor  34  services other tasks and subroutines. Therefore, a buffer that allows data to be written at one rate and read at another is needed. This is accomplished with FIFO memory, generally indicated at  35 - 38 , which has two separate ports for the input (written) data and the output (read) data. There is a separate clock for each data port. 
     The entire reclocking process is handled in two steps. The first step occurs when the microprocessor  34  moves the data into two concurrent 2Meg blocks of system memory  33 . It initially fills both sections and then waits until one block is emptied by the reading process. As the read pointer transitions into the second block of system memory  33 , the microprocessor  34  is notified to refill the first block. The refill cycle of the first block can be completed faster than the second block is emptied. This cycle of refilling the empty blocks continues until the system is stopped by the control circuitry. The next step is performed by four 512 byte blocks of FIFO memory  35 - 38 . The second stage adds another level of buffering to the system memory  33  and provides another important step. Data in the hard drive  32  and system memory  33  are stored and manipulated in 32 bit wide words. The output of this system must be 8 bits wide. The 32 bit words from the system memory  33  are distributed across the four 8 bit FIFO&#39;s  35 - 38  by a bus master device  40  via the PCI bus  41 . In the same manner as the system memory  33 , the bus master  40  and separate control logic microprocessor  42  break each FIFO  35 - 38  into two sections. The sections are refilled as the read pointer transitions across the half full boundary of each device. The output is then taken sequentially from each of the 8 bit FIFOs  35 - 38  at the required rate and width. 
     The control logic maintains a constant flow of data to the output at one of two rates: 
     19.392658 megabits per second or 2.424082 megabytes per second. 
     21.524475 megabits per second or 2.690559 megabytes per second. 
     The 19.392658 megabits per second rate is the bit rate for the MPEG transport stream. This is the output data when the raw MPEG data is stored on the hard drive  32 . The 21.524475 megabits per second rate is the bit rate required when the MPEG data is preencoded. This rate takes into account the data overhead required to store the Reed-Solomon error correction data and the additional field syncs. 
     Referring to FIG. 4, a data transfer block diagram of the new apparatus shows a more detailed view of the transfer method used to produce a fixed output data rate necessary to generate an HDTV signal for demonstration purposes. FIG. 4 shows a little more detail of how the 32-bit add on bus is split into four 8-bit bytes. Each byte is routed to an input FIFO  46 - 49 , an output FIFO  51 / 54  and a bidirectional buffer  55 - 58  for the add on microprocessor&#39;s data bus  60 . The local (add-on) microprocessor  61  handles the control commands between the local hardware and the system PC via mailboxes in the AMCC S 5933  bus master device. The local control software resides in the EPROM  62  which has a dedicated address bus and shares its data bus with the rest of the local devices. 
     The 8-bit local bus  65  is a bidirectional bus that all of the incoming and outgoing data share. This necessitates additional bidirectional buffers  63 ,  64  in the data path to eliminate the possibility of bus contention that can be caused by more than one device trying to actively drive the data bus. 
     Two different input and output standards are supported by this system, including TTL and LVDS. Input and output buffers are also included to convert the data to the appropriate levels for their parallel data ports. One additional buffer is used to transfer the data to another system board that develops the  8 VSB modulated signal. 
     This transfer method provides a cost effective means of retrieving video data that has been stored on a consumer type hard drive and produces a fixed rate data interface for the MPEG transport system. 
     Applicant&#39;s present invention, as shown in both embodiments, provides a new and improved means for displaying working HDTVs  11  and also servicing high definition television monitors when there is, as yet, no television broadcast stations in the nation that are running with HDTV broadcast signals. The present invention provides an inexpensive means of demonstrating high definition TVs. It may be loaded with HDTV program material or user created program material for the purpose of showing the capabilities of the HDTV technology. It is essentially a television broadcast station in a box  15 . It will provide all that a television station would provide if it were available. In fact, it is a much more flexible means of demonstrating HDTV. It can be controlled by a salesperson  13  allowing him to change the program material for the customer  12 . This is something one could not do with a broadcast HDTV signal. 
     While two embodiments of the present invention have been shown and described, it will be understood that changes and additions to the embodiments may be made within the scope of the present invention. It is the aim of the present invention to cover all such changes and modifications within the scope of the appended claims.