Simplified digital to sin/cos converter

Claim 2

A digital to sin/cos converter comprising: a. first means for providing a single reference sinusoidal waveform from a standard having a predetermined operating frequency; b. second means coupled to said standard and to input digital positional information in the form of azimuth change pulses for providing output sampling pulses representative of said input positional information; c. third means coupled to said first means and said second means for referencing same to one another in response to input digital reference information in the form of azimuth reference pulses; and d. fourth means coupling said sinusoidal reference waveform and said sampling pulses for providing resultant sinusoidal and cosinusoidal outputs equivalent to said input digital positional information in response to a sampling of said single reference waveform by said sampling pulses.

Claim 3

The arrangement according to claim 1 wherein said first means including a first n-stage counter arrangement coupled to said frequency standard for providing an output signal of predetermined reduced frequency relative to said standard, and fifth means coupled to said first n-stage counter output signal for providing an output constituting said single stabilized sinusoidal reference waveform of predetermined frequency.

Claim 4

The arrangement according to claim 2 wherein second means includes a second n-stage counter arrangement providing an output signal of predetermined reduced frequency relative to said standard, and mixing means coupling said standard and said input digital positional information to said second n-stage counter arrangement for providing to said second counter a pulse for each cycle received from said standard and an additional pulse for each received element of said input positional information, so as to advance said second counter relative to said first counter by an amount equivalent to one count per each received element of said input positional information.

Claim 5

The arrangement according to claim 3 wherein said second means further includes a 90*-count detector, input coupled to said output of said second n-stage counter and to the n-1 stage thereof, for providing an output sampling pulse having a phase of 90* relative to each sampling pulse of said second counter output.

Claim 6

The arrangement according to claim 4 wherein said third means includes bistable means for presetting the n-stages of said second counter arrangement to the setting of the n-stages of said first counter arrangement in 1-to-1 correspondence in dependence upon the receipt by said bistable means of an element of said input digital reference information.

Claim 7

The arrangement according to claim 5 wherein said bistable means includes a bistable element having the set input thereof coupled to said input digital reference information, the reset input thereof coupled to the output signal of said first n-stage counter arrangement, and an output thereof coupled to said second n-stage counter arrangement, whereby said second counter is cleared whenever said bistable device is reset by an output from said first counter occurring when said second counter clears following a setting of said bistable device due to a received element of said input digital reference information.

Claim 8

THe arrangement according to claim 4 wherein said second n-stage counter arrangement includes an n-bit counter portion and an (m-n)-significant bit counter portion, and wherein said third means includes an n-bit accumulator input coupled to said input positional information and coupled to said n-bit counter portion of said second n-stage counter arrangement by way of a plurality of individual connections, and bistable means, input coupled to said input reference information and to the output of said first n-stage counter arrangement and output coupled to said n-bit counter portion and said (m-n)-bit counter portion of said second n-stage counter arrangement, for setting the stages of said second n-stage counter arrangement in accordance with the accumulated information in said accumulator in dependence upon said bistable means being set by said input reference information and reset by the output of said first n-stage counter arrangement.

Claim 9

The arrangement according to claim 4 wherein each corresponding stage of said first and second n-stage counter arrangements are coupled in 1-to-1 correspondence, and wherein said third means includes bistable means, input coupled to said input reference information and to the output of said frequency standard and output coupled to strobe means which in turn is coupled to said second n-stage counter arrangement, for presetting the stages of said second n-stage counter arrangement to equal the corresponding stages of said first n-stage counter arrangement in response to a resetting of said bistable means by way of said frequency standard output each time said bistable means is set by said input reference information.

Claim 10

In a radar system employing digital antenna rotational information, a digital to sin/cos of azimuth converter comprising: a. first means for providing a single reference sinusoidal waveform from a standard having a predetermined operating frequency, said first means including an n-stage counter arrangement coupled to said frequency standard and providing an output signal of predetermined reduced frequency relative to said standard, and second means coupled to said first n-stage counter output for generating in response thereto a stabilized sinusoidal reference waveform of said predetermined frequency; b. third means coupled to input digital positional information and said standard, for providing output sampling pulses representative of said input positional information, said third means including a second n-stage counter arrangement providing an output signal of predetermined reduced frequency relative to said standard, and mixing means coupling said standard and said input digital positional information to said second n-stage counter arrangement for providing a pulse for each cycle received from each standard and an additional pulse for each received element of said input positional information, thereby advancing said second counter arrangement relative to said first counter arrangement by an amount equivalent to one count per each received element of said input positional information; c. fourth means coupled to said first means and said third means for referencing same to one another in response to input digital reference information in the form of azimuth reference pulses; and d. fifth means coupling said sinusoidal reference waveform and said sampling pulses for providing resultant sinusoidal and cosinusoidal outputs equivalent to said input digital positional information in response to a sampling of said single reference waveform by said sampling pulses.

Claim 11

In a radar system employing digital antenna rotational information, a digital to sin/cos of azimuth converter comprising: a. first means for providing a single reference sinusoidal waveform from a standard having a predetermined operating frequency, said first means including an n-stage counter arrangement coupled to said frequency standard and providing an output signal of predetermined reduced frequency relative to said standard, and second means coupled to said first n-stage counter output for generating in response thereto a stabilized sinusoidal reference waveform of said predetermined frequency; b. third means coupled to input digital positional information and said standard, for providing output sampling pulses representative of said input positional information, said third means including a second n-stage counter arrangement providing an output signal of predetermined reduced frequency relative to said standard, and mixing means coupling said standard and said input digital positional information to said second n-stage counter arrangement for providing a pulse for each cycle received from each standard and an additional pulse for each received element of said input positional information, thereby advancing said second counter arrangement relative to said first counter arrangement by an amount equivalent to one count per each received element of said input positional information; c. fourth means coupled to said first means and said third means for referencing same to one another in response to input digital reference information in the form of azimuth reference pulses; and d. fifth means coupling said sinusoidal reference waveform and said sampling pulses for providing resultant sinusoidal and cosinusoidal outputs equivalent to said input digital positional information in response to a sampling of said single reference waveform by said sampling pulses.