Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
  • H04N5/50—Tuning indicators; Automatic tuning control
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
  • H03J1/00—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
  • H03J1/0008—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
  • H03J7/00—Automatic frequency control; Automatic scanning over a band of frequencies
  • H03J7/02—Automatic frequency control
  • H03J7/04—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant
  • H03J7/06—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant using counters or frequency dividers
  • H03J7/065—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant using counters or frequency dividers the counter or frequency divider being used in a phase locked loop
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
  • H03J7/00—Automatic frequency control; Automatic scanning over a band of frequencies
  • H03J7/18—Automatic scanning over a band of frequencies
  • H03J7/20—Automatic scanning over a band of frequencies where the scanning is accomplished by varying the electrical characteristics of a non-mechanically adjustable element
  • H03J7/22—Automatic scanning over a band of frequencies where the scanning is accomplished by varying the electrical characteristics of a non-mechanically adjustable element in which an automatic frequency control circuit is brought into action after the scanning action has been stopped
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
  • H04N21/438—Interfacing the downstream path of the transmission network originating from a server, e.g. retrieving encoded video stream packets from an IP network
  • H04N21/4383—Accessing a communication channel
  • H04N21/4384—Accessing a communication channel involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/41—Structure of client; Structure of client peripherals
  • H04N21/426—Internal components of the client ; Characteristics thereof
  • H04N21/42607—Internal components of the client ; Characteristics thereof for processing the incoming bitstream
  • H04N21/4263—Internal components of the client ; Characteristics thereof for processing the incoming bitstream involving specific tuning arrangements, e.g. two tuners
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/04—Synchronising

Definitions

• the invention relates to a television system comprising a tuner for tuning video signals, a controller for controlling said tuner, and a stage for receiving tuned signals from said tuner and for supplying at least one control signal to said controller.
• the invention also relates to a controller, a method and a processor program product for use in a television system.
• a prior art system is known from US 4,763,195, which discloses a television system comprising a tuner for tuning RF (radio frequency) signals (video signals), and a microprocessor (controller) for controlling said tuner, and an IF (intermediate frequency) stage for receiving tuned signals from said tuner and for supplying an automatic fine tuning signal (at least one control signal) to said microprocessor (controller).
• a first search for identifying active channels is limited to only predictable non-standard frequencies associated with major cable distribution networks, and a second search for identifying active channels includes more search frequencies and extends over a wider frequency range. During an auto- programming mode, only the first search is conducted to minimize time.
• the known television system is disadvantageous, inter alia, due to requiring too much time for detecting an active channel: the automatic fine timing signal is a time- consuming signal due to including detections of humps (US 4,763,195 - col. 8).
• the television system comprises a tuner for tuning video signals, and a controller for controlling said tuner, and a stage for receiving tuned signals from said tuner and for supplying at least one control signal to said controller, wherein said stage comprises a phase-locked-loop, with said control signal comprising a lock signal originating from said phase-locked-loop.
• said controller when controlling said tuner, said controller generates and supplies signals to said tuner for defining the operating frequencies for said tuner.
• This tuner usually also comprises a phase-locked-loop, but this tuner-phase-locked- loop is just for locking a tuner oscillator at said operating frequencies. Therefore, this tuner- phase-locked-loop is different from said phase-locked-loop in said stage located after said tuner and does not supply said lock signal to said controller.
• the oscillator in said tuner-phase-locked-loop is controlled by said controller.
• a first embodiment of the television system according to the invention is defined by claim 2.
• Said controller comprises the switch for, in dependence of said lock signal, taking into account said synchronization signal (in case of said lock signal having a confirming value) or not (in case of said lock signal having a denying value). This synchronization signal is more time-consuming than said lock-signal.
• the television system can perform high speed tuning and detect active channels faster than prior art television systems.
• a second embodiment of the television system according to the invention is defined by claim 3.
• a fast tuning mode controlling said tuner such that one or more frequencies nearby one or more active channels are detected, through getting first and possibly second indications, high speed tuning is performed, while in a fine tuning mode, one or more channel frequencies are identified.
• a third embodiment of the television system according to the invention is defined by claim 4.
• said control signal further comprising the fine tuning signal to said controller, for example in said fine tuning mode, all active channels present can be identified.
• a fourth embodiment of the television system according to the invention is defined by claim 5.
• Said frequency table can be either a real table comprising all predefined frequencies or can be a starting predefined frequency together with one or more frequency steps (possibly per frequency band) to be taken for finding subsequent predefined frequencies.
• a fifth embodiment of the television system according to the invention is defined by claim 6.
• Embodiments of the controller according to the invention and of the method according to the invention and of the processor program product according to the invention correspond with the embodiments of the system according to the invention.
• the invention is based upon an insight, inter alia, that fine tuning signals are time-consuming signals which are not strictly necessary for making high-speed tuning searches, and is based upon a basic idea, inter alia, that lock signals originating from phase- locked-loops in intermediate frequency stages can give a first indication whether a channel is active or not (at a tuned frequency).
• the invention solves the problem, inter alia, of providing a television receiver which gets more quickly a first indication whether a channel is active or not (at a tuned frequency), and is advantageous, inter alia, in that this first indication forms a first foundation for high speed tuning and detecting active channels faster than prior art television systems, with said second indication forming a further advantageous second foundation for said high speed tuning.
• Fig. 1 illustrates in block diagram form a television system according to the invention comprising a controller according to the invention
• Fig. 2 illustrates in the form of a software stage machine a controller according to the invention
• Fig. 3 illustrates in flow chart form a method according to the invention and/or a processor program product according to the invention.
• the television system according to the invention shown in Fig. 1 comprises a tuner 1 with an amplifier 11 coupled to an antenna for receiving and amplifying modulated video signals and to an amplifier/mixer 12 for amplifying and mixing signals originating from amplifier 11.
• Amplifier/mixer 12 is coupled to a voltage-controlled-oscillator (VCO) 13 for receiving a first oscillation signal from NCO 13 necessary for said mixing.
• NCO 13 is coupled to a frequency divider 14 controlled by a dividing ratio setting unit 15 for dividing a second oscillation signal from NCO 13 by a ratio defined by setting unit 15.
• a comparator 16 is located between said divider 14 and a reference generator 17 for comparing the divided second oscillation signal and a reference signal originating from generator 17. Comparator 16 is further coupled to NCO 13 for supplying a comparison signal to said NCO 13 for controlling purposes.
• Amplifier/mixer 12 is further coupled to intermediate frequency stage 3 for supplying tuned signals to said stage 3, which comprises a demodulator 33 for demodulating said tuned signals and for supplying video signals to a synchronisation generator 4 and which comprises an automatic fine tuning unit 32 for receiving said tuned signals and for generating a fine tuning signal 52.
• Demodulator 33 is controlled by a phase-locked-loop 31 that generates a control signal comprising a lock signal 53.
• This lock signal 53 for example corresponds with a phase-locked-loop lock bit derived from an alternating current content of an oscillator input signal in said phase-locked-loop 31.
• Synchronisation generator 4 comprises a picture synchronisation information block 41 for receiving said video signals from said demodulator 33 and for receiving an oscillation signal from a deflection oscillator 42.
• Block 41 generates a synchronisation signal 54.
• Controller 2 comprises a processor 21 for receiving said lock signal 53, said fine tuning signal 52 and, via a switch 22, said synchronization signal 54, which switch 22 is controlled by said lock signal 53.
• Processor 21 is coupled to a memory 23 and generates a setting signal to be supplied to setting unit 15 for controlling tuner 1.
• Fig. 2 illustrates in the form of a software stage machine a controller according to the invention.
• a first software stage 60 corresponds with the start of the software stage machine and with writing an initial frequency in tuner 1 (goto 61).
• a second software stage 61 checks for a synchronisation signal and if present stores the corresponding channel in a non- volatile memory (goto 62).
• a third software stage 62 increments the frequency by a factor (goto 64 if the highest frequency has been reached, otherwise goto 63).
• a fourth software stage 63 checks for a lock signal (goto 61 if present otherwise goto 62).
• a fifth software stage 64 corresponds with the end of the software stage machine.
• the television system according to the invention as shown in Fig. 1 functions in view of Fig. 2 for example as follows.
• tuner 1 is controlled by controller 2 such that such that one or more frequencies nearby one or more active channels are detected: by using for example a frequency table stored in memory 23 for predefining a number of channels, dependently upon the part of the world in which said television system is going to serve a television audience, this number of channels can be predefined.
• Said frequency table can be a starting predefined frequency together with one or more frequency steps (possibly per frequency band) to be taken for finding subsequent predefined frequencies, as shown by software stages 60 and 62.
• said frequency table may be a real table comprising all predefined frequencies.
• the lock signal 53 from phase-locked-loop 31 in stage 3 is used as a control signal for controller 2, to get a first indication whether a channel is active or not (at a tuned frequency), as shown by software stage 63.
• a channel is active or not (at a tuned frequency)
• an active channel may be present (at a tuned frequency); but in case of said lock signal 53 having a denying (or non-confirming) value (goto software stage 62), an active channel will not be present (at a tuned frequency).
• the synchronization signal 54 from said synchronization generator 4 is used as a further control signal, to get a second indication whether a channel is active or not (at a tuned frequency), as shown by software stage 61.
• Controller 2 comprises switch 22 for, in dependence of said lock signal 53, taking into account said synchronization signal 54 (in case of said lock signal 53 having a confirming value) or not (in case of said lock signal 53 having a denying value). If the synchronisation signal 54 indicates synchronisation, the corresponding channel is stored in a non- volatile memory (like for example memory 22), as shown by software stage 61.
• the television system can perform high speed tuning and detect active channels faster than prior art television systems.
• tuner 1 is controlled by controller 2 such that one or more channel frequencies are identified (thereby for example using said fine tuning signal 52).
• this fast tuning mode and fine tuning mode further the following.
• tuner 1 is controlled by controller 2 in such a way that tuner 1 is tuned to 175.25 MHz. Due to lock signal 53 still being available in case of the tuned frequency and the channel frequency being about two MHz away from each other, lock signal 53 in this case of one MHz distance between the tuned frequency and the channel frequency will get a confirming value.
• this frequency 175.25 MHz is then finally stored.
• the fine tuning mode for example in case of the television audience selecting this particular channel to be watched, the exact channel frequency is found, in this case 174.25 MHz.
• Block 70 Start, goto 71.
• Block 71 High speed (or fast) Inning mode, goto 72.
• Block 72 Start tuning at 48.25 MHz, goto 73.
• Block 73 Has lock signal 53 a confirming value? If yes goto 74, if no goto 75.
• Block 74 Has sync signal 54 a confirming value? If yes goto 76, if no goto 75.
• Block 75 Is the tuning frequency > 303 MHz ? If yes goto 78, if no goto 77.
• Block 76 Store the channel, goto 79.
• Block 77 Add 7 MHz to the tuning frequency and a delay of 20 ms, goto 79.
• Block 78 Add 8 MHz to the tuning frequency and a delay of 20 ms, goto 79.
• Block 79 Is the tuning frequency > 856 MHz ? If yes goto 80, if no goto 73.
• Block 80 Normal (or fine) tuning mode, goto 81.
• Block 81 End.
• the flow chart shown in Fig. 3 is an example for the Asia Pacific Region.
• Each (part of each) block 70-81 and each transition between each two block 70-81 can be a
• Phase-locked-loop 31 can for example be implemented according to phase- locked-loop 13,14,16,17. Further units/blocks in tuner 1, stage 3, synchronization generator 4 and controller 2 are not to be excluded, like for example in general registers, buffers, filters etc. and more specifically a phase- 1 -loop with a phase- 1 -comparator and a horizontal oscillator in synchronization generator 4 etc.
• Switch 22 is just an example of a possible way to take into account said synchronization signal 54 dependently upon a value of lock signal 53, other ways are not to be excluded, like gates, latches, switching buffers/amplifiers etc. Of course, usually switch 22 will be (functionally) integrated into processor 21.

Landscapes

• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Television Receiver Circuits (AREA)
• Channel Selection Circuits, Automatic Tuning Circuits (AREA)
• Circuits Of Receivers In General (AREA)
• Management, Administration, Business Operations System, And Electronic Commerce (AREA)
• Time Recorders, Dirve Recorders, Access Control (AREA)
• Selective Calling Equipment (AREA)
• Details Of Television Systems (AREA)

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Publications (1)

Family

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Family Applications (1)

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Citations (4)

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• 2003
  • 2003-09-18 US US10/530,305 patent/US7643099B2/en not_active Expired - Fee Related
  • 2003-09-18 DE DE60323119T patent/DE60323119D1/de not_active Expired - Lifetime
  • 2003-09-18 JP JP2004541059A patent/JP4372009B2/ja not_active Expired - Fee Related
  • 2003-09-18 AT AT03799013T patent/ATE405987T1/de not_active IP Right Cessation
  • 2003-09-18 AU AU2003263477A patent/AU2003263477A1/en not_active Abandoned
  • 2003-09-18 WO PCT/IB2003/004154 patent/WO2004032322A1/en not_active Ceased
  • 2003-09-18 EP EP03799013A patent/EP1556950B1/en not_active Expired - Lifetime
  • 2003-09-18 CN CNB038238683A patent/CN100544202C/zh not_active Expired - Lifetime

Patent Citations (4)

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