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US3649909A Expired / Lapsed US ⏱️ 0.0 years remaining

Wide band phase lock spectral purity measuring apparatus

Assignee: United States Department of the Navy
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Filing: 1970-07-08
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Granted: 1972-03-14
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Expires: 1990-07-08
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Abstract

Abstract For phase locked measurements of spectral purity of radar transmitters, a comb generator provides harmonics of a crystal oscillator output signal which are applied through a phase shifter and a variable filter to furnish a reference frequency. The transmitter output signal is combined with the reference frequency in a mixer whose IF output is applied to a phase detector along with the output signal of a voltage-controlled oscillator. After rough adjustment of the oscillator, the phase detector output is fed back through a DC amplifier and low pass filter to the control input of the oscillator to maintain quadrature phase lock allowing FM sideband detection. The phase detector output may be passed to a wave analyzer and recording means or passed through a set of tuned bandpass filters and respective threshold detectors arranged to drive indicator means.

Inventors

  • 👤 Eldon L Ort
  • 👤 John K Smith
  • 👤 John A Kacergis

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 04:19
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/40; G01S7/4004; G01S7/4008; G01R; G01R23/00

Claims Analysis

Total Claims: 14
Claim 1
Independent Claim 137 words
Spectral purity measuring apparatus comprising: means for providing a predetermined fixed frequency; means adapted to receive said fixed frequency and an RF transmitter output for producing an IF replica output of said transmitter output; variable oscillator means for producing an output frequency whose phase is variable by means of a control signal input; phase detector means having a first input connected to receive the IF replica output and a second input connected to receive the variable oscillator means output for producing an output indicative of phase quadrature of said first and second phase detector means inputs; feedback means connected to receive phase detector means output for producing said control signal input to said variable oscillaTor means; and means connected to receive said phase detector means output for indicating the signal level thereof in a plurality of bandwidths.
Claim 2
Dependent Claim 137 words
Spectral purity measuring apparatus comprising: means for providing a predetermined fixed frequency; means adapted to receive said fixed frequency and an RF transmitter output for producing an IF replica output of said transmitter output; variable oscillator means for producing an output frequency whose phase is variable by means of a control signal input; phase detector means having a first input connected to receive the IF replica output and a second input connected to receive the variable oscillator means output for producing an output indicative of phase quadrature of said first and second phase detector means inputs; feedback means connected to receive phase detector means output for producing said control signal input to said variable oscillaTor means; and means connected to receive said phase detector means output for indicating the signal level thereof in a plurality of bandwidths.
Claim 3
Dependent Claim 209 words
Spectral purity apparatus comprising: means adapted to receive an RF transmitter output for producing an IF replica output thereof including a fixed frequency oscillator, means connected to receive the output of said fixed frequency oscillator for generating harmonics thereof, filter means connected to receive the output of said harmonic generating means for producing an output containing selected ones of said harmonics, mixer means having a first input adapted to operatively receive the RF transmitter output and a second input operatively connected to receive the filter means output for combining the signals at said first and second mixer means inputs to produce said IF replica output; variable oscillator means for producing an output frequency whose phase is variable by means of a control signal input; phase detector means having a first input connected to receive the IF replica output and a second input connected to receive the variable oscillator means output for producing an output indicative of phase quadrature of said first and second phase detector means inputs; feedback means connected to receive the phase detector means output for producing said control signal input to said variable oscillator means; and means connected to receive said phase detector means output for indicating the signal level thereof in a plurality of bandwidths.
Claim 4
Dependent Claim 209 words
Spectral purity apparatus comprising: means adapted to receive an RF transmitter output for producing an IF replica output thereof including a fixed frequency oscillator, means connected to receive the output of said fixed frequency oscillator for generating harmonics thereof, filter means connected to receive the output of said harmonic generating means for producing an output containing selected ones of said harmonics, mixer means having a first input adapted to operatively receive the RF transmitter output and a second input operatively connected to receive the filter means output for combining the signals at said first and second mixer means inputs to produce said IF replica output; variable oscillator means for producing an output frequency whose phase is variable by means of a control signal input; phase detector means having a first input connected to receive the IF replica output and a second input connected to receive the variable oscillator means output for producing an output indicative of phase quadrature of said first and second phase detector means inputs; feedback means connected to receive the phase detector means output for producing said control signal input to said variable oscillator means; and means connected to receive said phase detector means output for indicating the signal level thereof in a plurality of bandwidths.
Claim 5
Dependent Claim 53 words
Measuring apparatus according to claim 2 wherein: said means for indicating the signal level comprises a wave analyzer connected to receive said phase detector means output and producing an output representing the level of said phase detector means output as a function of frequency and recording means for indicating said wave analyzer output.
Claim 6
Dependent Claim 98 words
Measuring apparatus according to claim 2 wherein: said signal level indicating means comprises a plurality of band-pass filters each connected to receive said phase detector means output for producing respective outputs indicating the signal level within each respective filtered band, a plurality of threshold detectors connected respectively to receive the outputs of said plurality of band-pass filters for providing respective output signals when the outputs of said band-pass filters exceed respective threshold levels and display mean operatively connected to receive the outputs of said plurality of threshold detectors for indicating the respective conditions of the threshold detector outputs.
Claim 7
Dependent Claim 45 words
Measuring apparatus according to claim 2 wherein: said feedback means includes amplifying means connected to receive said phase detector means output and low-pass filter means connected to receive the output of said amplifying means for producing said control signal input to said variable oscillator means.
Claim 8
Dependent Claim 35 words
Measuring apparatus according to claim 5 further comprising: means operatively connected to receive said phase detector means output for indicating whether said first and second inputs to said phase detector means are in phase quadrature.
Claim 9
Dependent Claim 17 words
Measuring apparatus according to claim 6 wherein: said means for indicating phase quadrature comprises null detection means.
Claim 10
Dependent Claim 279 words
Apparatus for measuring the spectral content of a transmitter output, comprising: a fixed frequency oscillator; comb generator means connected to receive the output of said fixed frequency oscillator for producing harmonics thereof; variable filter means operatively receiving the output of said comb generator means for selecting predetermined ones of said harmonics; mixer means having a first input adapted to operatively receive the transmitter output and a second input operatively connected to receive the output of said variable filter means for combining the signals at said first and second inputs to produce an IF replica of said transmitter output; phase detector meanS having first and second inputs for producing an output indicative of the phase difference between the signals at said first and second phase detector means inputs, said first input being connected to receive the mixer means output; voltage controlled oscillator means for producing an output frequency whose phase is variable by means of a control signal input, said phase detector means second input being connected to receive the output of said voltage-controlled oscillator; amplifying means connected to receive said phase detector means output; filter means connected to receive the output of said amplifying means for providing said control signal input to said voltage-controlled oscillator; a plurality of band-pass filters connected respectively to receive said phase detector means output; and a plurality of threshold detector means connected to receive the respective outputs of said band-pass filters for providing respective outputs indicating whether the levels within the filtered bands exceed respective thresholds, the output of said plurality of threshold detector means being adapted to be connected to display means for indicating the conditions of the respective threshold detector means outputs.
Claim 11
Dependent Claim 279 words
Apparatus for measuring the spectral content of a transmitter output, comprising: a fixed frequency oscillator; comb generator means connected to receive the output of said fixed frequency oscillator for producing harmonics thereof; variable filter means operatively receiving the output of said comb generator means for selecting predetermined ones of said harmonics; mixer means having a first input adapted to operatively receive the transmitter output and a second input operatively connected to receive the output of said variable filter means for combining the signals at said first and second inputs to produce an IF replica of said transmitter output; phase detector meanS having first and second inputs for producing an output indicative of the phase difference between the signals at said first and second phase detector means inputs, said first input being connected to receive the mixer means output; voltage controlled oscillator means for producing an output frequency whose phase is variable by means of a control signal input, said phase detector means second input being connected to receive the output of said voltage-controlled oscillator; amplifying means connected to receive said phase detector means output; filter means connected to receive the output of said amplifying means for providing said control signal input to said voltage-controlled oscillator; a plurality of band-pass filters connected respectively to receive said phase detector means output; and a plurality of threshold detector means connected to receive the respective outputs of said band-pass filters for providing respective outputs indicating whether the levels within the filtered bands exceed respective thresholds, the output of said plurality of threshold detector means being adapted to be connected to display means for indicating the conditions of the respective threshold detector means outputs.
Claim 12
Dependent Claim 14 words
Apparatus according to claim 8 wherein: said mixer means is a Shottky barrier diode.
Claim 13
Dependent Claim 240 words
Apparatus for measuring the spectral content of an external signal having a nominal carrier frequency, comprising: fixed frequency oscillator means; comb generator means connected to receive the output of the said fixed frequency oscillator for providing harmonics thereof; variable filter means operatively connected to receive the output of said comb generator means for selecting predetermined ones of said harmonics; mixer means having a first input operatively connected to receive the output of said variable filter means and a second input adapted to receive said external signal for combining the signals at said first and second inputs to produce an IF output frequency; phase detector means having first and second inputs for producing an input indicative of the phase difference between the signals at said first and second inputs, said first input being connected to receive the output of said mixer means, said phase detector means output being adapted to be connected to display means for indicating the level of said phase detector means output in a plurality of discrete bandwidths; voltage-controlled oscillator means for producing an output frequency whose phase is variable by means of a control signal input, said phase detector means second input being connected to receive the output of said voltage-controlled oscillator means; amplifying means connected to receive said phase detector means output; and filter means connected to receive the output of said amplifying means for providing said control signal input to said voltage controlled oscillator means.
Claim 14
Dependent Claim 240 words
Apparatus for measuring the spectral content of an external signal having a nominal carrier frequency, comprising: fixed frequency oscillator means; comb generator means connected to receive the output of the said fixed frequency oscillator for providing harmonics thereof; variable filter means operatively connected to receive the output of said comb generator means for selecting predetermined ones of said harmonics; mixer means having a first input operatively connected to receive the output of said variable filter means and a second input adapted to receive said external signal for combining the signals at said first and second inputs to produce an IF output frequency; phase detector means having first and second inputs for producing an input indicative of the phase difference between the signals at said first and second inputs, said first input being connected to receive the output of said mixer means, said phase detector means output being adapted to be connected to display means for indicating the level of said phase detector means output in a plurality of discrete bandwidths; voltage-controlled oscillator means for producing an output frequency whose phase is variable by means of a control signal input, said phase detector means second input being connected to receive the output of said voltage-controlled oscillator means; amplifying means connected to receive said phase detector means output; and filter means connected to receive the output of said amplifying means for providing said control signal input to said voltage controlled oscillator means.

References Cited (Backward Citations)

US2888643A Cited
US3059187A Cited
US3215934A Cited
US3154741A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-03-14 1975-09-13 1976-03-14 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-03-14 1979-09-13 1980-03-14 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-03-14 1983-09-13 1984-03-14 $7700.00 Window Closed / Lapsed

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