Digital to analogue servosystem

Claim 2

A digital to analogue converter comprising: an impedance ladder network means having a plurality of inputs for receiving fine and coarse digital information and providing output signals proportions thereto, said ladder network means including a first section having a plurality of interconnected weighted impedances and an analogue output terminal for providing a fine analogue output proportional to the fine digital input to said first section, and a second section having a plurality of interconnected weighted impedances for receiving said coarse digital information and having an analogue input terminal and an analogue output terminal; and unity gain noninverting amplifier means having an input connected with the analogue output terminal of said first section for receiving said fine analogue output signals and having an output coupled with the analogue input of said second section for applying said fine analogue output signals as an input to said second section, the output of said amplifier providing said fine analogue output as an output signal and said analogue output of said second section providing analogue output signals proportional to said fine and coarse digital information.

Claim 3

A digital to analogue converter comprising: an impedance ladder network means having a plurality of inputs for receiving digital information and including a first section having a plurality of interconnected weighted impedances and an analogue output terminal, and a second section having a plurality of interconnected weighted impedances having an analogue input terminal and an analogue output terminal; said first section including a first group of weighted impedances having their first ends connected to a first group of said inputs for receiving digital information and their second ends connected to a first group of taps, and a second group of weighted impedances each connected between respective taps, with one of said taps providing analogue output terminal of said first section; said second section including a first group of weighted impedances having their first ends connected to a second group of said inputs for receiving digital information and their second ends connected to a second group of taps, and including a second group of weighted impedances connected between respective taps, first and second taps of said second section respectively providing said analogue input and analogue output terminals thereof; each of the impedances of the first group of weighted impedances of each section having a value twice that of each of the impedances of the second group of weighted impedances of each section; and amplifier means having an input connected with the analogue output terminal of said first section and having an output coupled with the analogue input of said second section, the output of said amplifier and said analogue output of said second section providing analogue outputs for said converter.

Claim 4

A digital to analogue converter comprising: an impedance ladder network means having a plurality of inputs for receiving digital information and including a first section having a plurality of interconnected weighted impedances and an analogue output terminal, and a second section having a plurality of interconnected weighted impedances having an analogue input terminal and an analogue output terminal; said first section including a first group of weighted impedances having their first ends connected to a first group of said inputs for receiving digital information and their second ends connected to a first group of taps, and a second group of weighted impedances each connected between respective taps, with one of said taps providing analogue output terminal of said first section; said second section including a first group of weighted impedances having their first ends connected to a second group of said inputs for receiving digital information and their second ends connected to a second group of taps, and including a second group of weighted impedances connected between respective taps, first and second taps of said second section respectively providing said analogue input and analogue output terminals thereof; each of the impedances of the first group of weighted impedances of each section having a value twice that of each of the impedances of the second group of weighted impedances of each section; and amplifier means having an input connected with the analogue output terminal of said first section and having an output coupled with the analogue input of said second section, the output of said amplifier and said analogue output of said second section providing analogue outputs for said converter.

Claim 5

A converter as in claim 2 wherein said amplifier means includes a feedback amplifier and an impedance coupled to the output thereof weighted the same as each impedance of said first groups of impedances, and the output of said amplifier is connected through an impedance weighted the same as each impedance of said second groups of impedances to the analogue input of said second section.

Claim 6

A converter as in claim 3 wherein said weighted impedances are resistances with the resistance of the resistances in said second groups having a value R and the resistance of the resistances in said first groups having a value 2R.

Claim 7

A digital to analogue servosystem comprising: conversion means having a plurality of input terminals for receiving digital data, said conversion means including electrically weighted networks respectively having first and second analogue output terminals, said networks having a predetermined electrical ration therebetween; first and second comparison means having first inputs respectively connected with said first and second output terminals of said conversion means, said comparison means providing respective first and second error output signals as a function of input signals applied to said respective first inputs and feedback signals applied to respective second inputs thereof; switching means connected with the outputs of said first and second comparison means for passing either said first or second error signal to an output thereof; electrical to mechanical conversion means connected with the output of said switching means for providing a mechanical output; first and second mechanical to electrical conversion means having electrical feedback outputs respectively connected with said second inputs of said first and second comparison means; and mechanical coupling means coupling the output of said electrical to mechanical conversion means to the mechanical inputs of said first and second mechanical to electrical conversion means, said mechanical coupling means including gearing means providing a gear ratio between the output of said electrical to mechanical conversion means and the mechanical input of said second mechanical to electrical conversion means, said gear ratio being the same as said predetermined electrical ratio.

Claim 8

A digital to analogue servosystem comprising: conversion means having a plurality of input terminals for receiving digital data, said conversion means including electrically weighted networks respectively having first and second analogue output terminals, said networks having a predetermined electrical ration therebetween; first and second comparison means having first inputs respectively connected with said first and second output terminals of said conversion means, said comparison means providing respective first and second error output signals as a function of input signals applied to said respective first inputs and feedback signals applied to respective second inputs thereof; switching means connected with the outputs of said first and second comparison means for passing either said first or second error signal to an output thereof; electrical to mechanical conversion means connected with the output of said switching means for providing a mechanical output; first and second mechanical to electrical conversion means having electrical feedback outputs respectively connected with said second inputs of said first and second comparison means; and mechanical coupling means coupling the output of said electrical to mechanical conversion means to the mechanical inputs of said first and second mechanical to electrical conversion means, said mechanical coupling means including gearing means providing a gear ratio between the output of said electrical to mechanical conversion means and the mechanical input of said second mechanical to electrical conversion means, said gear ratio being the same as said predetermined electrical ratio.

Claim 9

A system as in claim 5 wherein: said electrical to mechanical conversion means includes amplifier means connected with the output of said switching means for controlling a motor which in turn moves an output shaft; and said output shaft is coupled with the mechanical input of saiD first mechanical to electrical conversion means, and coupled through said gearing means to the mechanical input of said second mechanical to electrical conversion means.

Claim 10

A digital to analogue servosystem comprising: conversion means having a plurality of input terminals for receiving digital data, and having at least first and second analogue output terminals; first and second comparison means having first inputs respectively connected with said first and second output terminals of said conversion means, said comparison means providing respective first and second error output signals as a function of input signals applied to said respective first inputs and feedback signals applied to respective second inputs thereof; switching means connected with the outputs of said first and second comparison means for passing either said first or second error signal to an output thereof, said switching means including a resistance connected between the output of said s first comparison means and a common terminal, a diode network connected between the output of said second comparison means and said common terminal, and a diode network connected between a reference terminal and said common terminal, said common terminal serving as the output of said switching means; electrical to mechanical conversion means connected with the output of said switching means for providing a mechanical output; first and second mechanical to electrical conversion means having electrical feedback outputs respectively connected with said second inputs of said first and second comparison means; and mechanical coupling means coupled to the output of said electrical to mechanical conversion means to the mechanical input of said first and second mechanical to electrical conversion means.

Claim 11

A digital to analogue servosystem comprising: conversion means having a plurality of input terminals for receiving digital data, and having at least first and second analogue output terminals; first and second comparison means having first inputs respectively connected with said first and second output terminals of said conversion means, said comparison means providing respective first and second error output signals as a function of input signals applied to said respective first inputs and feedback signals applied to respective second inputs thereof; switching means connected with the outputs of said first and second comparison means for passing either said first or second error signal to an output thereof, said switching means including a resistance connected between the output of said s first comparison means and a common terminal, a diode network connected between the output of said second comparison means and said common terminal, and a diode network connected between a reference terminal and said common terminal, said common terminal serving as the output of said switching means; electrical to mechanical conversion means connected with the output of said switching means for providing a mechanical output; first and second mechanical to electrical conversion means having electrical feedback outputs respectively connected with said second inputs of said first and second comparison means; and mechanical coupling means coupled to the output of said electrical to mechanical conversion means to the mechanical input of said first and second mechanical to electrical conversion means.

Claim 12

A digital to analogue servosystem comprising: conversion means having a plurality of input terminals for receiving digital data and having fine and coarse analogue output terminals, said conversion means including electrically weighted networks having a predetermined electrical ratio therebetween; first and second comparison means having first inputs respectively connected with said fine and coarse output terminals, said comparison means providing respective first and second error output signals as a function of input signals applied to said respective first inputs and feedback signals applied to respective second inputs thereof; switching means connected with the outputs of said first and second comparison means for passing either said first and second comparison means for passing either said first or second error signal to an output thereof; mechanical motion producing means connected with the output of said switching means for providing a mechanical motion output; first and second variable impedance means providing electrical feedback signals respectively connected with said second inputs of said first and second comparison means, said first variable impedance means including at least first and second variable impedances each having an impedance element with an electrical gap at the ends thereof, said gaps being displaced with respect to each other, and each of said variable impedances having a wiper for contacting the impedance element thereof, said impedance element and wiper of each variable impedance being relatively movable with respect to one another in proportion to said mechanical motion output, and switching means electrically connected to the wiper of said variable impedances, said switching means providing feedback signals to said first comparison means by providing selectable electrical paths between either of said wipers and said first comparison means; and mechanical coupling means responsive to the mechanical motion output of said mechanical motion producing means to control the operation of said variable impedance means, said mechanical coupling means including means for controlling said first variable impedance means, and gearing means for conTrolling said second variable impedance means, said gearing means having a ratio proportional to said electrical ratio.

Claim 13

A digital to analogue servosystem comprising: conversion means having a plurality of input terminals for receiving digital data and having fine and coarse analogue output terminals, said conversion means including electrically weighted networks having a predetermined electrical ratio therebetween; first and second comparison means having first inputs respectively connected with said fine and coarse output terminals, said comparison means providing respective first and second error output signals as a function of input signals applied to said respective first inputs and feedback signals applied to respective second inputs thereof; switching means connected with the outputs of said first and second comparison means for passing either said first and second comparison means for passing either said first or second error signal to an output thereof; mechanical motion producing means connected with the output of said switching means for providing a mechanical motion output; first and second variable impedance means providing electrical feedback signals respectively connected with said second inputs of said first and second comparison means, said first variable impedance means including at least first and second variable impedances each having an impedance element with an electrical gap at the ends thereof, said gaps being displaced with respect to each other, and each of said variable impedances having a wiper for contacting the impedance element thereof, said impedance element and wiper of each variable impedance being relatively movable with respect to one another in proportion to said mechanical motion output, and switching means electrically connected to the wiper of said variable impedances, said switching means providing feedback signals to said first comparison means by providing selectable electrical paths between either of said wipers and said first comparison means; and mechanical coupling means responsive to the mechanical motion output of said mechanical motion producing means to control the operation of said variable impedance means, said mechanical coupling means including means for controlling said first variable impedance means, and gearing means for conTrolling said second variable impedance means, said gearing means having a ratio proportional to said electrical ratio.

Claim 14

A system as in claim 8 wherein: said conversion means includes a first electrically weighted network having a tap, said tap being connected through amplifying means, the output of said amplifying means being coupled through a first weighted impedance to said fine analogue output terminal and through a second weighted impedance to a tap of a second electrically weighted network which includes another tap serving as said coarse analogue output terminal; and said tap of said first network being couple to control the operation of said switching means.

Claim 15

A servosystem comprising: first and second comparison means having first inputs for receiving analogue signals, said analogue signals comprising fine and coarse analogue signals, the maximum values thereof having a predetermined ratio, said comparison means providing respective first and second error output signals as a function of input signals applied to said respective first inputs and feedback signals applied to respective second inputs thereof; switching means connected with the outputs of said first and second comparison means for passing either said first and second comparison means for passing either said first or second error signal to an output thereof as a function of said second error output signal; mechanical motion producing means connected with the output of said switching means for providing a mechanical motion output; first and second variable impedance means providing electrical feedback signals respectively connected with said second inputs of said first and second comparison means; and mechanical coupling means responsive to the mechanical motion output of said mechanical motion producing means to control the operation of said variable impedance means, said mechanical coupling means providing a mechanical coupling ratio between said first and second variable impedance means the same as said predetermined ratio.

Claim 16

A servosystem comprising: first and second comparison means having first inputs for receiving analogue signals, said analogue signals comprising fine and coarse analogue signals, the maximum values thereof having a predetermined ratio, said comparison means providing respective first and second error output signals as a function of input signals applied to said respective first inputs and feedback signals applied to respective second inputs thereof; switching means connected with the outputs of said first and second comparison means for passing either said first and second comparison means for passing either said first or second error signal to an output thereof as a function of said second error output signal; mechanical motion producing means connected with the output of said switching means for providing a mechanical motion output; first and second variable impedance means providing electrical feedback signals respectively connected with said second inputs of said first and second comparison means; and mechanical coupling means responsive to the mechanical motion output of said mechanical motion producing means to control the operation of said variable impedance means, said mechanical coupling means providing a mechanical coupling ratio between said first and second variable impedance means the same as said predetermined ratio.

Claim 17

A digital to analogue servosystem comprising: conversion means for receiving digital data and providing analogue output signals, said conversion means comprising a pair of electrically weighted networks having input terminals for receiving said digital data and outputs for said analogue signals, the first of said networks serving to receive fine digital information and the second serving to receive coarse digital information, there being a predetermined electrical ratio between said fine and coarse digital information; amplifier means for receiving fine and coarse analogue information from said conversion means and supplying the same to an output, said amplifier means comprising a first amplifier having a first input for receiving fine analogue signals and a second input for receiving feedback signals, and including a second amplifier having a first input for receiving fine and coarse analogue signals and a second input for receiving feedback signals; means coupling the output of the first weighted network with the first input of said first amplifier for supplying said fine analogue signals from said first network to said first amplifier, and for supplying said fine information to an input of said second network, means coupling the output of said second network with the first input of said second amplifier to supply both fine and coarse analogue signals to said second amplifier; switching means coupled with the outputs of said first and second amplifiers for providing either fine output signals or fine and coarse output signals; and output means coupled with the output of said switching means for responding to said fine and coarse analogue signals and providing said feedback signals to said first and second amplifiers.

Claim 18

A digital to analogue servosystem comprising: conversion means for receiving digital data and providing analogue output signals, said conversion means comprising a pair of electrically weighted networks having input terminals for receiving said digital data and outputs for said analogue signals, the first of said networks serving to receive fine digital information and the second serving to receive coarse digital information, there being a predetermined electrical ratio between said fine and coarse digital information; amplifier means for receiving fine and coarse analogue information from said conversion means and supplying the same to an output, said amplifier means comprising a first amplifier having a first input for receiving fine analogue signals and a second input for receiving feedback signals, and including a second amplifier having a first input for receiving fine and coarse analogue signals and a second input for receiving feedback signals; means coupling the output of the first weighted network with the first input of said first amplifier for supplying said fine analogue signals from said first network to said first amplifier, and for supplying said fine information to an input of said second network, means coupling the output of said second network with the first input of said second amplifier to supply both fine and coarse analogue signals to said second amplifier; switching means coupled with the outputs of said first and second amplifiers for providing either fine output signals or fine and coarse output signals; and output means coupled with the output of said switching means for responding to said fine and coarse analogue signals and providing said feedback signals to said first and second amplifiers.

Claim 19

A system as in claim 11 including detector means coupled with the output of said second amplifier, said detector means having an output coupled with said switching means for cOntrolling the operation of said switching means to pass either the fine output of said first amplifier or the fine and coarse output of said second amplifier.

Claim 20

A system as in claim 11 wherein said output means includes a motor responsive to the signals from said switching means, said motor having an output shaft coupled with fine feedback means, said output shaft being coupled through gearing means to coarse feedback means, said gearing means having a ratio proportional to said ratio between said fine and coarse digital input signals, and said fine and coarse feedback means being respectively coupled to the second inputs of said first and second amplifiers.

Claim 21

A digital to analogue servosystem comprising: conversion means for receiving digital data and providing analogue output signals, said conversion means comprising a pair of electrically weighted networks having input terminals for receiving said digital data and outputs for said analogue signals, the first of said networks serving to receive fine digital information and the second serving to receive coarse digital information, there being a predetermined electrical ratio between said fine and coarse digital information; amplifier means connected with an output of said first network for providing a fine analogue output, the output of said amplifier means being coupled with an input os said second network, said second network having an output providing fine and coarse analogue output; error circuit means coupled with the output of said amplifier means and said output of said second network for selectively providing a fine analogue error output or a fine and coarse analogue error output; and output means coupled with the output of said error circuit means, said output means including a motor responsive to error signals from said error circuit means, said motor having an output shaft for providing a mechanical fine analogue output, mechanical coupling means coupling said output shaft to a second shaft which provides a mechanical coarse analogue output, said mechanical coupling means providing a ratio between said two shafts proportional to said ratio between said fine and coarse digital information.

Claim 22

A digital to analogue servosystem comprising: conversion means for receiving digital data and providing analogue output signals, said conversion means comprising a pair of electrically weighted networks having input terminals for receiving said digital data and outputs for said analogue signals, the first of said networks serving to receive fine digital information and the second serving to receive coarse digital information, there being a predetermined electrical ratio between said fine and coarse digital information; amplifier means connected with an output of said first network for providing a fine analogue output, the output of said amplifier means being coupled with an input os said second network, said second network having an output providing fine and coarse analogue output; error circuit means coupled with the output of said amplifier means and said output of said second network for selectively providing a fine analogue error output or a fine and coarse analogue error output; and output means coupled with the output of said error circuit means, said output means including a motor responsive to error signals from said error circuit means, said motor having an output shaft for providing a mechanical fine analogue output, mechanical coupling means coupling said output shaft to a second shaft which provides a mechanical coarse analogue output, said mechanical coupling means providing a ratio between said two shafts proportional to said ratio between said fine and coarse digital information.

Claim 23

A system as in claim 14 wherein said output means includes fine feedback means and coarse feedback means, said fine feedback means being coupled to said output shaft and said coarse feedback means being coupled to said second shaft, said fine and coarse feedback means supplying electrical feedback signals to said error circuit means.

Claim 24

A system as in claim 14 wherein said amplifier means comprises a unity gain noninverting differential amplifier.

Claim 25

A system as in claim 16 wherein said error circuit means comprises first and second differential amplifiers, the output of said unity gain amplifier being coupled to an input of said first differential amplifier, and the output of said second network being coupled to an input of said second differential amplifier.

Claim 26

A system as in claim 17 wherein said output means includes fine and coarse feedback means respectively coupled with said two shafts, said fine and coarse feedback means providing respective feedback signals to said first and second differential amplifiers.