US3701155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic direction finder
Assignee: MACKAY COMMUNICATIONS Inc CELWAVE SYSTEMS Inc PO BOX 39 CLARMONT NC 28610-0039 A CORP OF
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Filing: 1970-10-26
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Granted: 1972-10-24
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Expires: 1990-10-26
Abstract
Abstract A first radio frequency (RF) intermediate frequency (IF) section is coupled to a sense antenna which receives an RF signal to which direction is to be determined. The IF output signal of this first section is used to phase lock a reference oscillator to this IF output signal. The reference oscillator operates at a frequency eight times the IF frequency to prevent spurious signals from appearing in the circuitry. A digital divide-byeight frequency divider provides a first reference signal for phase locking the oscillator, a gate signal and a second reference signal which, together with the IF output of the first section, provides a visual indication of phase lock. A goniometer including a rotor and a pair of orthogonally disposed loop antennas also receive the RF signal for application to a second RF/IF section. The IF output signal of the second section is gated by the gate signal into an integrating amplifier. The output signal of the integrating amplifier is detected by a zero crossing detector whose output signal is applied to a squaring circuit and also a monostable multivibrator whose output signal drives a variable frequency (rate) pulse generator. The output signal of squaring circuit and the output signal of the pulse generator are operated on by logic circuitry whose output signal controls a stepper motor. The stepper motor mechanically adjusts the rotor of the goniometer to produce a null in the IF output signal of the second section. The rotor also moves a pointer to indicate relative bearing with respect to the bow. A gyro compass repeater may move a calibrated card or ring to display the true bearing of the signal.
Inventors
- 👤 Henry G Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:57
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/14; G01S3/38; G01S3/42; G01S3/04; G01S3/06
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
209 words
An automatic direction finder to determine the direction to a radio frequency signal source comprising: first means to receive said radio frequency signal and produce a first intermediate frequency signal having a given frequency and a given phase; second means including a goniometer to receive said radio frequency signal and produce a second intermediate frequency signal having said given frequency and a phase having a 90* phase relation to said given phase; a reference oscillator; third means coupled to said first means and said reference oscillator to phase lock said reference oscillator to said first intermediate frequency signal and to produce at least one gate signal having a given phase relationship with respect to said phase of said second intermediate frequency signal; fourth means coupled to said second means and said third means responsive to said one gate signal to gate said second intermediate frequency signal and to integrate said gated second intermediate frequency signal; fifth means coupled to the output of said fourth means to produce a control signal proportional to the deviation from a null in said second intermediate frequency signal; and sixth means coupled to said goniometer and said fifth means responsive to said control signal to achieve said null in said second intermediate frequency signal.
Claim 2
Dependent Claim
209 words
An automatic direction finder to determine the direction to a radio frequency signal source comprising: first means to receive said radio frequency signal and produce a first intermediate frequency signal having a given frequency and a given phase; second means including a goniometer to receive said radio frequency signal and produce a second intermediate frequency signal having said given frequency and a phase having a 90* phase relation to said given phase; a reference oscillator; third means coupled to said first means and said reference oscillator to phase lock said reference oscillator to said first intermediate frequency signal and to produce at least one gate signal having a given phase relationship with respect to said phase of said second intermediate frequency signal; fourth means coupled to said second means and said third means responsive to said one gate signal to gate said second intermediate frequency signal and to integrate said gated second intermediate frequency signal; fifth means coupled to the output of said fourth means to produce a control signal proportional to the deviation from a null in said second intermediate frequency signal; and sixth means coupled to said goniometer and said fifth means responsive to said control signal to achieve said null in said second intermediate frequency signal.
Claim 3
Dependent Claim
29 words
A direction finder according to claim 1, further including seventh means coupled to said first means and said third means to provide a visual indication of said phase lock.
Claim 4
Dependent Claim
25 words
A direction finder according to claim 1, further including seventh means coupled to said fifth means to provide a visual indication of achieving said null.
Claim 5
Dependent Claim
27 words
A direction finder according to claim 1, further including seventh means coupled to said first means to provide an aural indication of receiving said radio frequency signal.
Claim 6
Dependent Claim
17 words
A direction finder according to claim 1, wherein said third means includes a digital phase locked loop.
Claim 7
Dependent Claim
30 words
A direction finder according to claim 1, wherein said reference oscillator generates a frequency having a value N times said given frequency, where N is an integer greater than one.
Claim 8
Dependent Claim
37 words
A direction finder according to claim 6, wherein N is equal to eight, and said third means includes a digital phase locked loop having a digital divide-by-eight frequency divider, said frequency divider producing said one gate signal.
Claim 9
Dependent Claim
21 words
A direction finder according to claim 1, wherein said fifth means includes a zero crossing detector to produce said control signal.
Claim 10
Dependent Claim
134 words
A direction finder according to claim 1, wherein said reference oscillator generates a frequency having a value eight times said given frequency; and said third means includes a sine wave to square wave converter coupled to said first means, a digital divide-by-eight frequency divider coupled to said reference oscillator providing in addition to said one gate signal, a first reference signal having a nominal phase 90* out of phase with respect to said given phase, a digital phase comparator coupled to said converter and said frequency divider responsive to the square wave output of said converter and said first reference signal to produce a phase control signal, and a low pass filter coupled between said comparator and said reference oscillator to couple said phase control signal to said reference oscillator for phase control thereof.
Claim 11
Dependent Claim
60 words
A direction finder according to claim 9, wherein said comparator includes an EXCLUSIVE OR gate coupled to said converter and said frequency divider responsive to the square wave output of said converter and said first reference signal, and an operational amplifier having a threshold level coupled to the output of said EXCLUSIVE OR gate to produce said phase control signal.
Claim 12
Dependent Claim
108 words
A direction finder according to claim 9, wherein said frequency divider provides in addition to said one gate signal and said first reference signal, a second reference signal having a nominal phase 180* out of phase with respect to said given phase; and further including an EXCLUSIVE OR gate coupled to said converter and said frequency divider responsive to the square wave output of said converter and said second reference signal, an operational amplifier having a threshold level coupled to the output of said EXCLUSIVE OR gate, and a visual indicator coupled to the output of saId operational amplifier to provide a visual indication of said phase lock.
Claim 13
Dependent Claim
189 words
A direction finder according to claim 11, wherein said frequency divider includes a first JK-flip-flop coupled to be triggered by the output signal of said oscillator on its trigger input and provide a divide-by-two output signal on its output, a second JK-flip-flop coupled to said first flip-flop triggered by said output signal of said first flip-flop on its trigger input, a third JK-flip-flop coupled to said first flip-flop triggered by said output signal of said first flip-flop on its trigger input, the output of said second flip-flop being coupled to the J input of said third flip-flop, the complementing output of said second flip-flop being coupled to the K input of said third flip-flop, the output of said third flip-flop being coupled to the K input of said second flip-flop, and the complementing output of said third flip-flop being coupled to the J input of said second flip-flop, said one gate signal being provided at the output of said second flip-flop, said first reference signal being provided at the output of said third flip-flop, and said second reference signal being provided at the complementing output of said second flip-flop.
Claim 14
Dependent Claim
167 words
A direction finder according to claim 1, wherein said fourth means includes a gate circuit coupled to said second means and said third means to gate said second intermediate frequency signal to the output of said gate circuit by said one gate signal, and a first operational amplifier coupled to the output of said gate circuit to integrate said gated second intermediate frequency signal; said fifth means includes a second operational amplifier coupled to the output of said first operational amplifier to detect the zero crossings of said gated second intermediate frequency signal to produce said control signal; and said sixth means includes a squaring circuit coupled to the output of said second operational amplifier, a monostable multivibrator coupled to the output of said second operational amplifier, a variable rate pulse generator coupled to the output of said multivibrator, and logic circuitry coupled to the output of said pulse generator, the output of said squaring circuit and said goniometer to control said goniometer to achieve said null.
Claim 15
Dependent Claim
29 words
A direction finder according to claim 13, further including a visual indicator coupled to the output of said squaring circuit to provide a visual indication of achieving said null.
Claim 16
Dependent Claim
158 words
A direction finder according to claim 1, wherein said first means includes a vertical antenna responding to the electric field component of said radio frequency signal, a first radio frequency amplifier coupled to said vertical antenna, a local oscillator, a first mixer coupled to said first radio frequency amplifier and said local oscillator to produce said first intermediate frequency signal, and a first intermediate frequency amplifier coupled to said first mixer; and said second means includes said goniometer having a rotor coupled to said sixth means to achieve said null, and a pair of orthogonally related loop antennas responding to the magnetic field component of said radio frequency signal, said rotor being coupled to said loop antennas, a second radio frequency amplifier coupled to said rotor, a second mixer coupled to said second radio frequency amplifier and said local oscillator to produce said second intermediate frequency signal, and a second intermediate frequency amplifier coupled to said second mixer.
Claim 17
Dependent Claim
294 words
A direction finder according to claim 15, wherein said reference oscillator generates a frequency having a value eight times said given frequency; said third means includes a sine wave to square wave converter coupled to said first intermediate frequency amplifier, a digital divide-by-eight Frequency divider coupled to said reference oscillator providing in addition to said one gate signal, a reference signal having a nominal phase 90* out of phase with respect to said given phase, a digital phase comparator coupled to said converter and said frequency divider responsive to the square wave output of said converter and said reference signal to produce a phase control signal, and a low pass filter coupled between said comparator and said reference oscillator to couple said phase control signal to said reference oscillator for phase control thereof; said fourth means includes a gate circuit coupled to said second intermediate frequency amplifier and said frequency divider to gate said second intermediate frequency signal to the output of said gate circuit by said one gate signal, and a first operational amplifier coupled to the output of said gate circuit to integrate said gated second intermediate frequency signal; said fifth means includes a second operational amplifier coupled to the output of said first operational amplifier to detect the zero crossings of said gated second intermediate frequency signal to produce said control signal; and said sixth means includes a squaring circuit coupled to the output of said second operational amplifier, a monostable multivibrator coupled to the output of said second operational amplifier, a variable rate pulse generator coupled to the output of said multivibrator, and logic circuitry coupled to the output of said pulse generator, the output of said squaring circuit and said goniometer to control said rotor to achieve said null.
References Cited (Backward Citations)
US3390392A
Cited
US3611386A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |