Digital-to-resolver converter

Claim 2

A digital-to-resolver converter comprising a first transformer having a primary for receiving a fixed reference voltage input and a pair of secondaries with each secondary being provided with a plurality of taps, a switch provided in each of said taps, means for selectively simultaneously closing a selected switch to each of said secondaries, said last named means being arranged to receive a first portion of a binary digital order and to convert said portion to a signal to close said selected pair of switches such that one secondary will be provided with an analog voltage corresponding to the sine of a primary angle indicated by said digital order while the other secondary will be simultaneously provided with an analog voltage corresponding to the cosine of said primary angle, a second and a third transformer each having a primary winding electrically connected with one of said secondaries of said first transformer, each of said second and third transformers having a pair of secondary windings with a first secondary winding matching the number of turns in the associated primary winding and a secondary winding having a smaller number of turns than said primary winding and being provided with a plurality of taps, a switch provided in each of said taps of said second secondary windings, means for selectively simultaneously closing one switch to each of said second secondary windings, said last named means being arranged to receive a second portion of said binary digital order and to convert said portion to a signal to close a selected pair of said switches such that each of said second secondary windings are provided with an analog voltage corresponding to the tangent of an incremental angle indicated by said digital order times the analog voltage received from said first transformer, said first secondary windings of said second and third transformers being serially connected with the second secondary windings of said third and second transformers, respectively, whereby the outputs of said second and third transformers are analog voltages corresponding to the sine of the sum of said primary angle and said incremental angle and corresponding to the cosine of the sum of said primary angle and said incremental angle.

Claim 3

A digital-to-resolver converter according to claim 1 including fourth and fifth transformers each being provided with a primary winding electrically connected with one of the secondary windings of the second and third transformers, each of said fourth and fifth transformers having a pair of secondary windings with a first secondary winding matching the number of turns in the associated primary winding and a second secondary winding having a smaller number of turns than said primary winding and being provided with a plurality of taps, a switch provided in each of said taps of said second secondary winding of said fourth and fifth transformers, means for selectively simultaneously closing one switch to each of said second secondary windings of said fourth and fifth transformers, said last named means being arranged to receive a third portion of said binary digital order and to convert said portion to a signal to close a selected pair of said switches sucH that each of said second secondary windings are provided with an analog voltage corresponding to the tangent of a second incremental angle indicated by said digital order times the analog voltage received from said second or third transformers, said first secondary windings of said fourth and fifth transformers being serially connected with the second secondary windings of said fifth and fourth transformers, respectively, whereby the outputs of said fourth and fifth transformers are analog voltages corresponding to the sine of the sum of said primary angle and said incremental angles and corresponding to the cosine of the sum of said primary angle and said incremental angles.

Claim 4

A digital-to-resolver converter according to claim 1 wherein said transformer taps in the secondary windings of said second and third transformers are uniformly spaced along said second secondary windings.

Claim 5

A digital-to-resolver converter according to claim 1 wherein said switches comprise solid state bipolar elements having two separate and independent contacts with one in each of said secondary windings.

Claim 6

A digital-to-resolver converter according to claim 4 wherein each of said switches comprises a dual-emitter transistor biased in the grounded collector configuration with said signal being applied thereto at the base, and means for biasing said base in the absence of a digital order signal so that it is more positive than the maximum positive value of the reference voltage on the associated transformer winding.

Claim 7

A digital-to-resolver converter according to claim 5 wherein said means for selectively closing said switches comprises a binary to decimal converter and driver having a plurality of leads connected to the bases of said transistors, each of said leads being open when unactuated and being arranged to conduct current through said base biasing means when actuated to lower the voltage at said base to a negative value.

Claim 8

A digital-to-resolver converter comprising a first transformer having a primary for receiving a fixed reference voltage input and a pair of secondaries with each secondary being provided with a plurality of taps; a switch provided in each of said taps; means for selectively simultaneously closing a selected switch to each of said secondaries, said last-named means being arranged to receive a first portion of a binary digital order and to convert said portion to a signal to close said selected pair of switches such that one secondary will be provided with an analog voltage corresponding to the sine of a primary angle indicated by said first portion of the digital order while the other secondary will be simultaneously provided with an analog voltage corresponding to the cosine of said primary angle; a second and third transformer, the output of each secondary of said first transformer being center-tapped into the primary winding of one of said second or said third transformers; means for receiving a second portion of said binary digital order and converting it to analog voltages upon certain of the secondary windings of said second and third transformers such that the outputs of said second and third transformers are analog voltages corresponding to the sine of the sum of said primary angle and an incremental angle indicated by the second portion of said digital order and corresponding to the cosine of the sum of said primary angle and said incremental angle; one end of the primary winding of each of the second and the third transformers being connected through a first quadrant switch to ground and the other end of the primary winding of each of the second and the third transformers being connected through a second quadrant switch to ground; and means for connecting for simultaneous closure a selected pair of the four possible intertransformer combinations of quadrant switches whereby said analog voltages representing the sine and the cosine of the sum of said primary angle and incremental angle can be continuously obtained through a complete 360* cyclE with one of said selected pairs of quadrant switches being closed during each quadrant of the cycle and such that said switching is accomplished from a secondary of the first transformer to a portion of one of the primary windings of the second and third transformers only when the voltage is zero on said portion in order to prevent the generation large transient voltages in switching, each of said quadrant switches comprising double-pole switches having one pole connecting an end of one transformer primary to ground and the other pole connecting an end of the other transformer primary to ground.

Claim 9

A digital-to-resolver converter comprising a first transformer having a primary for receiving a fixed reference voltage input and a pair of secondaries with each secondary being provided with a plurality of taps; a switch provided in each of said taps; means for selectively simultaneously closing a selected switch to each of said secondaries, said last-named means being arranged to receive a first portion of a binary digital order and to convert said portion to a signal to close said selected pair of switches such that one secondary will be provided with an analog voltage corresponding to the sine of a primary angle indicated by said first portion of the digital order while the other secondary will be simultaneously provided with an analog voltage corresponding to the cosine of said primary angle; a second and third transformer, the output of each secondary of said first transformer being center-tapped into the primary winding of one of said second or said third transformers; means for receiving a second portion of said binary digital order and converting it to analog voltages upon certain of the secondary windings of said second and third transformers such that the outputs of said second and third transformers are analog voltages corresponding to the sine of the sum of said primary angle and an incremental angle indicated by the second portion of said digital order and corresponding to the cosine of the sum of said primary angle and said incremental angle; one end of the primary winding of each of the second and the third transformers being connected through a first quadrant switch to ground and the other end of the primary winding of each of the second and the third transformers being connected through a second quadrant switch to ground; and means for connecting for simultaneous closure a selected pair of the four possible intertransformer combinations of quadrant switches whereby said analog voltages representing the sine and the cosine of the sum of said primary angle and incremental angle can be continuously obtained through a complete 360* cyclE with one of said selected pairs of quadrant switches being closed during each quadrant of the cycle and such that said switching is accomplished from a secondary of the first transformer to a portion of one of the primary windings of the second and third transformers only when the voltage is zero on said portion in order to prevent the generation large transient voltages in switching, each of said quadrant switches comprising double-pole switches having one pole connecting an end of one transformer primary to ground and the other pole connecting an end of the other transformer primary to ground.

Claim 10

A digital-to-resolver converter according to claim 7 wherein each of said quadrant switches comprises a bipolar transistor biased in the grounded collector configuration and having a pair of emitters connected to the ends of said transformer primary windings, said signal being applied to said transistor at the base thereof.

Claim 11

A digital-to-resolver converter according to claim 8 including means for biasing said base of the transistor in the absence of a digital order signal so that it is more positive than the maximum positive value of twice the reference voltage.

Claim 12

In a digital-to-resolver converter comprising a first transformer having a pair of secondary windings, means for generating a voltage corresponding to the sine of a given angle on one of the secondary windings and for generating a voltage corresponding to the cosine of a given angle on the other secondary winding, a second and third transformer connected to receive respectively said generated voltages, and means for generating within one of said second and third transformers a voltage corresponding to the sine of the sum of said given angle and an incremental angle and for generating within the other of said second and third transformers a voltage corresponding to the cosine of the sum of said given angle and said incremental angle; the improvement comprising a plurality of spaced grounded taps in each of said secondary windings of the first transformer; a switch in each of said taps arranged to be selectively actuated by digital signals indicative of said sine and cosine of said given angle with said digital signals being defined by two voltage input levels with one of said levels being at ground potential; each switch comprising a bipolar transistor having its collector grounded and its base connected to receive said digital signals and being provided with a pair of emitters, one of said emitters being connected to one of the secondary windings of said first transformer and the other emitter being connected to the other secondary winding of said first transformer.

Claim 13

In a digital-to-resolver converter comprising a first transformer having a pair of secondary windings, means for generating a voltage corresponding to the sine of a given angle on one of the secondary windings and for generating a voltage corresponding to the cosine of a given angle on the other secondary winding, a second and third transformer connected to receive respectively said generated voltages, and means for generating within one of said second and third transformers a voltage corresponding to the sine of the sum of said given angle and an incremental angle and for generating within the other of said second and third transformers a voltage corresponding to the cosine of the sum of said given angle and said incremental angle; the improvement comprising a plurality of spaced grounded taps in each of said secondary windings of the first transformer; a switch in each of said taps arranged to be selectively actuated by digital signals indicative of said sine and cosine of said given angle with said digital signals being defined by two voltage input levels with one of said levels being at ground potential; each switch comprising a bipolar transistor having its collector grounded and its base connected to receive said digital signals and being provided with a pair of emitters, one of said emitters being connected to one of the secondary windings of said first transformer and the other emitter being connected to the other secondary winding of said first transformer.