Analog voltage generators for television tuners

Claim 2

In a television receiver having at least one voltage controlled tuner, a channel selection system for tuning said voltage controlled tuner comprising: a source of reference voltage; first and second resistor ladder networks having a respective first and second plurality of series coupled resistor elements, a respective first and second plurality of output terminals, ones of said first plurality of output terminals being paired with ones of said second plurality of output terminals such that the voltage difference between terminals of said pAirs is substantially equal to the voltage required to tune said voltage controlled tuner over a plurality of channels, said ladder networks further having respective input terminals, said input terminals coupled in parallel to said source of reference voltage a channel selection means for providing control signals responsive to selection of particular television channels; first and second gating means receptive to signals from said channel selection means and respectively coupled to said plurality of output terminals of said first and second ladder networks for providing respective first and second output signals responsive to a selected channel a third resistor ladder network having first and second input terminals respectively coupled to said first and second output terminals of said first and second gating means and a plurality of output terminals; and coupling means responsive to said control signals for coupling a selected one of said output terminals of said third network to said tuner and providing a tuning voltage thereto.

Claim 3

Apparatus according to claim 1 wherein said gating means includes: a plurality of transfer gates having input terminals coupled to respective output terminals of said first and second ladders, output terminals coupled to said third ladder and control terminals coupled to said selecting means.

Claim 4

Apparatus according to claim 2 wherein said coupling means includes: a plurality of gates having input terminals coupled to respective output terminals of said third ladder, control terminals coupled to said selecting means and output terminals coupled in common to said tuner.

Claim 5

Apparatus according to claim 3 wherein: said first and second resistor ladder networks include a plurality of potentiometers coupled to particular ones of said ladder output terminals for varying the voltage provided thereby.

Claim 6

Apparatus according to claim 4 wherein said third resistor ladder network includes: ten series coupled resistors adapted for receiving a current from said source of reference voltage, nine output terminals at the intersections of adjacent resistor elements and a tenth output terminal at an end of said ten series coupled resistors.

Claim 7

Apparatus according to claim 5 wherein said channel selection means includes: a plurality of switches for providing electrical signals responsive to numerical channel commands; and means for storing signals provided by said switches.

Claim 8

Apparatus according to claim 6 wherein said means for storing signals includes: first and second registers for respectively storing signals representative of the tens and units portions of selected television channel number.

Claim 9

Apparatus according to claim 3 wherein: said first resistor ladder network includes a series of at least six resistance elements arranged in series for receiving current from said source of reference voltage and at least five output terminals separated by ones of said resistance elements for providing five different voltages; and said second resistor ladder network includes a series of at least five resistance elements arranged in series for receiving current from said source of reference voltage and at least four output terminals adjacent to different ones of said five resistance elements for providing four different output voltages.

Claim 10

Apparatus according to claim 8 wherein said third resistor ladder network includes: ten series coupled resistors adapted for receiving a current from said source of reference voltage, nine output terminals at the intersections of adjacent resistor elements and a tenth output terminal at an end of said ten series coupled resistors.

Claim 11

Apparatus according to claim 9 wherein said channel selection means includes: a plurality of switches for providing electrical signals responsive to numerical channel commands; and means for storing signals provided by said switches.

Claim 12

Apparatus according to claim 10 wherein said Means for storing signals includes: first and second registers for respectively storing signals representative of the tens and units portions of selected television channel number.

Claim 13

A channel selector for a television receiver having a voltage controlled tuner comprising: selecting means for providing an output signal in response to a selected channel; a source of reference voltage; a first resistor ladder network having at least six resistance elements arranged in series for receiving current from said source of reference voltage and at least five output terminals separated by ones of said resistance elements for providing five different voltages corresponding to particular television channels; a second resistor ladder network having at least five resistance elements arranged in series for receiving current from said source of reference voltage and at least four output terminals adjacent to different ones of said five resistance elements for providing four different output voltages that are less than the voltages provided at corresponding output terminals on said first ladder and greater than the voltage provided at a next adjacent output terminal on said first ladder, said output voltage provided by said second ladder further corresponding to particular other television channels; a third resistor ladder network having a plurality of output terminals and first and second input terminals; switching means responsive to signals from said selecting means and interposed between said third network and said first and second networks for responsively switching said input terminals of said third network to respective ones of output terminals on said first and second networks such that the voltage on said first input terminal always exceeds the voltage on said second input terminal; and output means responsive to said selecting means for coupling signals from particular ones of said output terminals on said third network to said tuner.

Claim 14

A channel selector for a television receiver having a voltage controlled tuner comprising: selecting means for providing an output signal in response to a selected channel; a source of reference voltage; a first resistor ladder network having at least six resistance elements arranged in series for receiving current from said source of reference voltage and at least five output terminals separated by ones of said resistance elements for providing five different voltages corresponding to particular television channels; a second resistor ladder network having at least five resistance elements arranged in series for receiving current from said source of reference voltage and at least four output terminals adjacent to different ones of said five resistance elements for providing four different output voltages that are less than the voltages provided at corresponding output terminals on said first ladder and greater than the voltage provided at a next adjacent output terminal on said first ladder, said output voltage provided by said second ladder further corresponding to particular other television channels; a third resistor ladder network having a plurality of output terminals and first and second input terminals; switching means responsive to signals from said selecting means and interposed between said third network and said first and second networks for responsively switching said input terminals of said third network to respective ones of output terminals on said first and second networks such that the voltage on said first input terminal always exceeds the voltage on said second input terminal; and output means responsive to said selecting means for coupling signals from particular ones of said output terminals on said third network to said tuner.

Claim 15

Apparatus according to claim 12 wherein said third resistor ladder network includes: ten series coupled resistors adapted for receiving a current from said source of reference voltage, nine output terminals at the intersections of adjacent resistor elements and a tenth output terminal at an end of said ten series coupled resistors.

Claim 16

Apparatus according to claim 13 including: first and second buffer amplifiers coupled between said switching means and said respective input terminals of said third ladder network for providing a relatively high impedance load on said first and second ladders, and a relatively low impedance for driving said third ladder.

Claim 17

Apparatus according to claim 14 wherein said channel selection means includes: a plurality of switches for providing electrical signals responsive to numerical channel commands; and means for storing signals provided by said switches.

Claim 18

Apparatus according to claim 15 wherein said means for storing signals includes: first and second registers for respectively storing signals representative of the tens and units portions of selected television channel number.

Claim 19

A channel selector for a television receiver having a voltage controlled tuner comprising: selecting means for providing an output signal in response to a selected channel; a first resistor ladder network having a plurality of output terminals for providing a series of different voltages corresponding to particular television channels, said first resistor ladder network including at least five potentiometers in an alternating series with at least four fixed resistors, said five potentiometers each having an output terminal for providing output voltages each of which can be varied independently by an associated one of said five potentiometers to correspond to a particular television channel; a second resistor ladder network having at least four potentiometers and at least three fixed resistors arranged in an alternating series, saiD four potentiometers each having an output terminal for providing respective output voltages each of which can be varied independently by an associated one of said four potentiometers, said last-named output voltages being less than the voltages provided at corresponding output terminals on said first ladder and greater than the voltage provided at a next adjacent output terminal on said first ladder, said output voltages provided by said second ladder further corresponding to particular other television channels; a third resistor ladder network having a plurality of output terminals and first and second input terminals; switching means responsive to signals form said selecting means and interposed between said third network and said first and second networks for responsively switching said input terminals of said third network to respective ones of output terminals on said first and second networks such that the voltage on said first input terminal always exceeds the voltage on said second input terminal; and output means responsive to said selecting means for coupling signals from particular ones of said output terminals on said third network to said tuner.

Claim 20

A channel selector for a television receiver having a voltage controlled tuner comprising: selecting means for providing an output signal in response to a selected channel; a first resistor ladder network having a plurality of output terminals for providing a series of different voltages corresponding to particular television channels, said first resistor ladder network including at least five potentiometers in an alternating series with at least four fixed resistors, said five potentiometers each having an output terminal for providing output voltages each of which can be varied independently by an associated one of said five potentiometers to correspond to a particular television channel; a second resistor ladder network having at least four potentiometers and at least three fixed resistors arranged in an alternating series, saiD four potentiometers each having an output terminal for providing respective output voltages each of which can be varied independently by an associated one of said four potentiometers, said last-named output voltages being less than the voltages provided at corresponding output terminals on said first ladder and greater than the voltage provided at a next adjacent output terminal on said first ladder, said output voltages provided by said second ladder further corresponding to particular other television channels; a third resistor ladder network having a plurality of output terminals and first and second input terminals; switching means responsive to signals form said selecting means and interposed between said third network and said first and second networks for responsively switching said input terminals of said third network to respective ones of output terminals on said first and second networks such that the voltage on said first input terminal always exceeds the voltage on said second input terminal; and output means responsive to said selecting means for coupling signals from particular ones of said output terminals on said third network to said tuner.

Claim 21

Apparatus according to claim 17 wherein said third resistor ladder network includes: ten series coupled resistors adapted for receiving a current from said source of reference voltage, nine output terminals at the intersections of adjacent resistor elements and a tenth output terminal at an end of said ten series coupled resistors.