Memory-saving all channel digital tuning system
First Claim
1. A television tuning system including:
- a voltage controlled tuner having a nonlinear tuning voltage-versus-frequency characteristic;
memory means storing both reference tuning information, and increment tuning information related to the slope of said characteristic at each channel, said reference tuning information comprising nominal tuning information for a reference channel and said increment tuning information representing the changes in nominal tuning information between adjacent channels;
tuning voltage means generating a tuning voltage for said tuner;
channel address means accessing said memory means for tuning to a selected channel and reading out the corresponding tuning informations; and
accumulator means coupled between said memory means and said tuning voltage means algebraically adding tuning information increments to said reference tuning information to derive the nominal tuning information for the selected channel.
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Accused Products
Abstract
A tuning system for a television receiver includes fine tune memories and tuning information memories having reference channel nominal tuning information for each frequency band and increment tuning information representing the tuning voltage differences between successive channels. Accumulator means add the reference channel tuning information and increment information to develop the nominal tuning voltage for any selected channel. Control logic, including channel number counters and latches and state counters, is coupled to the accumulator means, tuning information memories and the fine tune memories. The memories'"'"' and accumulator means'"'"' outputs are coupled to a corresponding plurality of comparators which are also coupled to counters for deriving pulse-width modulated (PWM) signals corresponding to tuning information in the accumulator means and memories. The PWM signals are supplied to a tuning voltage generator where they are combined to produce the final tuning voltage for the tuner. The increment tuning information is representative of the slope of the tuning curve at each of the channel tuning points and is used to equalize any auxiliary tuning voltage source. The final tuning voltage consists of the derived nominal tuning voltage combined with the product of the fine tune voltage and channel increment tuning information.
10 Citations
19 Claims
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1. A television tuning system including:
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a voltage controlled tuner having a nonlinear tuning voltage-versus-frequency characteristic; memory means storing both reference tuning information, and increment tuning information related to the slope of said characteristic at each channel, said reference tuning information comprising nominal tuning information for a reference channel and said increment tuning information representing the changes in nominal tuning information between adjacent channels; tuning voltage means generating a tuning voltage for said tuner; channel address means accessing said memory means for tuning to a selected channel and reading out the corresponding tuning informations; and accumulator means coupled between said memory means and said tuning voltage means algebraically adding tuning information increments to said reference tuning information to derive the nominal tuning information for the selected channel. - View Dependent Claims (2, 3, 4)
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5. The method of operating a television tuning system including a tuner having a nonlinear tuning voltage-versus-frequency characteristic and a channel-number-accessible memory for storing tuning information, comprising the steps of:
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storing in said memory reference tuning information comprising nominal tuning information for a reference channel and tuning increment information representative of the change in nominal tuning information between successive channels; computing nominal tuning information for the selected channel by reading out from said memory and algebraically summing tuning increment informations and the reference channel tuning information to derive the nominal tuning information for the selected channel; and producing a tuning voltage therefrom for said tuner. - View Dependent Claims (6, 7)
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8. The method of operating a television tuning system including a tuner having a nonlinear tuning voltage-versus-frequency characteristic, a channel-number-accessible memory for storing tuning information, an arithmetic logic unit and a storage register comprising the steps of:
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storing in said memory (a) nominal tuning information for a pseudo channel having a frequency 6 MHz below the lowest numbered channel in the frequency band, and (b) increment tuning information for each channel corresponding to the tuning information change between successive channels including the pseudo channel; interrogating said memory for a desired channel to read out said pseudo channel tuning information and one or more of said increment informations; computing the nominal tuning voltage information for said desired channel from said pseudo channel information and said increment information by operating said arithmetic logic unit to combine said nominal tuning information for said pseudo channel and said increment information in said storage register, and producing a tuning voltage therefrom for said tuner. - View Dependent Claims (9, 10)
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11. A television tuning system including a voltage-controlled tuner having a nonlinear voltage-versus-frequency characteristic and a memory having a plurality of accessible locations;
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one of said locations storing nominal tuning information for a reference channel; others of said locations storing increment tuning information representative of changes in nominal tuning information between said reference channel and the next adjacent channel and between successive pairs of adjacent channels; a channel number counter for accessing said different memory locations in accordance with channel numbers; accumulator means coupled to said memory for developing nominal tuning information for a selected channel by reading out and combining said nominal tuning information for said reference channel with all increment informations between said reference channel and said selected channel; and a tuning voltage generator coupled to said accumulator means for generating a tuning voltage for said tuner from said developed nominal tuning information. - View Dependent Claims (12, 13, 14, 15, 16)
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17. An all-channel television tuning system including a voltage controlled tuner having a nonlinear voltage-versus-frequency characteristic and a memory having a plurality of locations each accessible by a distinct channel number, said channels being numbered consecutively but lying in more than one distinct frequency band;
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one of said locations in each distinct frequency band storing nominal tuning information for a reference channel in its associated band; others of said locations in each band storing increment tuning information representative of changes in nominal tuning information between the associated reference channel and the next adjacent channel and between successive pairs of adjacent channels in each band; a channel number counter; accumulator means coupled to said memory for developing nominal tuning information for any selected channel by combining the nominal tuning information for its associated reference channel with increment tuning information between the associated reference channel and the selected channel; a tuning voltage generator coupled to the said accumulator means for generating a tuning voltage for said tuner from said developed nominal tuning information; band decoder means determining the proper frequency band for each channel number; and memory location translation means for allocating blocks of memory locations to said different frequency bands. - View Dependent Claims (18, 19)
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Specification