US3918006A
Expired / Lapsed
US
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Digital frequency synthesizer including phase locked loop
Assignee: Cincinnati Electronics Corp
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Filing: 1974-09-27
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Granted: 1975-11-04
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Expires: 1994-09-27
Abstract
Abstract A digital frequency synthesizer includes a variable frequency oscillator that is mechanically tuned to one mHz intervals and electronically tuned to 50 kHz intervals by a phase locked loop control voltage. The phase locked loop includes a prescaler for dividing the oscillator frequency by a first predetermined factor. A preset counter frequency divides the output of the prescaler by a second predetermined factor and controls the occurrence times of frequency divided pulses in response to the selected 50 kHz interval. A frequency divider responds to a frequency standard to derive a reference frequency equal to the 50 kHz spacing between adjacent channels divided by the frequency dividing factor of the prescaler. A gate is opened at approximately the reference frequency for a length sufficiently wide to selectively pass not more than one of the frequency divided pulses during each cycle of the reference frequency. A phase detector responds to the reference frequency and the passed pulses for deriving the control voltage for the variable frequency oscillator, whereby the variable frequency oscillator output frequency is stabilized at the selected mHz and kHz values.
Inventors
- 👤 Clement W Munninghoff
- 👤 Francis A Wissel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:12
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/18; H03L7/183; H03L7/195; H03L7/193
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
225 words
A digital frequency synthesizer comprising a voltage controlled oscillator covering a number of frequency bands, means for selecting one of said bands, said oscillator being voltage controlled within each of said bands, a phase locked loop responsive to the frequency derived by the oscillator for deriving a control voltage for enabling the oscillator to derive a selected frequency channel within the selected band, said phase locked loop including: a prescaler for dividing the oscillator frequency by a first predetermined factor, preset counter means for frequency dividing the frequency derived from the prescaler by a second predetermined factor and for controlling the occurrence time of frequency divided pulses in response to the selected frequency channel, a frequency standard, frequency divider means responsive to the frequency standard for deriving a wave having a reference phase and a reference frequency equal to the spacing between adjacent channels divided by the first factor, means responsive to the frequency standard for deriving a gating signal having a frequency approximately equal to the reference frequency and a length sufficiently wide to enable not more than one of the frequency divided pulses to be passed during each cycle of the reference frequency, gate means responsive to the gating voltage and the frequency divided pulses, and phase detector means responsive to the reference frequency and the passed pulses for deriving the control voltage.
Claim 2
Dependent Claim
225 words
A digital frequency synthesizer comprising a voltage controlled oscillator covering a number of frequency bands, means for selecting one of said bands, said oscillator being voltage controlled within each of said bands, a phase locked loop responsive to the frequency derived by the oscillator for deriving a control voltage for enabling the oscillator to derive a selected frequency channel within the selected band, said phase locked loop including: a prescaler for dividing the oscillator frequency by a first predetermined factor, preset counter means for frequency dividing the frequency derived from the prescaler by a second predetermined factor and for controlling the occurrence time of frequency divided pulses in response to the selected frequency channel, a frequency standard, frequency divider means responsive to the frequency standard for deriving a wave having a reference phase and a reference frequency equal to the spacing between adjacent channels divided by the first factor, means responsive to the frequency standard for deriving a gating signal having a frequency approximately equal to the reference frequency and a length sufficiently wide to enable not more than one of the frequency divided pulses to be passed during each cycle of the reference frequency, gate means responsive to the gating voltage and the frequency divided pulses, and phase detector means responsive to the reference frequency and the passed pulses for deriving the control voltage.
Claim 3
Dependent Claim
25 words
The digital frequency synthesizer of claim 1 further including means for changing the length of the gating signal in response to the selected frequency band.
Claim 4
Dependent Claim
23 words
The digital frequency synthesizer of claim 2 wherein said changing means includes means for effectively counting the number of cycles of the oscillator.
Claim 5
Dependent Claim
54 words
The digital frequency synthesizer of claim 1 further including means for deriving a control signal in response to completion of the gating signal or the frequency divided pulse being passed, whichever occurs first, means for activating the preset counter means to a count determined by the selected channel in response to the control signal.
Claim 6
Dependent Claim
38 words
The digital frequency synthesizer of claim 4 wherein the means for deriving the gating signal includes further counter means responsive to the frequency standard, and means for resetting the further counter means in response to the control signal.
Claim 7
Dependent Claim
65 words
The digital frequency synthesizer of claim 1 further including means for deriving a control signal in response to completion of the gating signal or the frequency divided pulse being passed, whichever occurs first, and wherein the means for deriving the gating signal includes further counter means responsive to the frequency standard, and means for resetting the further counter means in response to the control signal.
Claim 8
Dependent Claim
75 words
The digital frequency synthesizer of claim 6 further including additional counting means responsive to the preset counter means, means responsive to the control signal for resetting the additional counting means, decoding circuitry responsive to the further counting means for deriving the gating signal while the further counting means is between a pair of counts, and means responsive to the additional counting means for changing the pair of counts to which the decoding means is responsive.
Claim 9
Dependent Claim
63 words
The digital frequency synthesizer of claim 1 further including means for deriving a control signal in response to completion of the gating signal or the frequency divided pulse being passed, whichever occurs first, and means for controlling the occurrence time, relative to the control signal being derived, and duration of the gating signal in response to the count of the additional counting means.
Claim 10
Dependent Claim
145 words
A digital frequency synthesizer comprising a voltage controlled oscillator, a phase locked loop responsive to the frequency derived from the oscillator for deriving a control voltage for enabling the oscillator to derive a selected frequency channel, said phase locked loop including: phase detector means for deriving the control voltage, frequency divider means responsive to the oscillator frequency for frequency dividing the oscillator frequency and for deriving a frequency divided output pulse having an occurrence time determined by the selected channel, means for deriving a wave having a reference phase and a reference frequency equal to a multiple of the frequency spacing between adjacent channels, said phase detector means being responsive to the reference frequency, and means synchronized with the reference wave for enabling not more than one frequency divided pulse to be passed to the phase detector means during each cycle of the reference frequency.
Claim 11
Dependent Claim
145 words
A digital frequency synthesizer comprising a voltage controlled oscillator, a phase locked loop responsive to the frequency derived from the oscillator for deriving a control voltage for enabling the oscillator to derive a selected frequency channel, said phase locked loop including: phase detector means for deriving the control voltage, frequency divider means responsive to the oscillator frequency for frequency dividing the oscillator frequency and for deriving a frequency divided output pulse having an occurrence time determined by the selected channel, means for deriving a wave having a reference phase and a reference frequency equal to a multiple of the frequency spacing between adjacent channels, said phase detector means being responsive to the reference frequency, and means synchronized with the reference wave for enabling not more than one frequency divided pulse to be passed to the phase detector means during each cycle of the reference frequency.
Claim 12
Dependent Claim
189 words
A digital frequency synthesizer for deriving a predetermined one of a plurality of frequency channels within a frequency band, said synthesizer being capable of covering a number of said bands, comprising a voltage controlled oscillator settable to said bands, means for activating the oscillator so that it has an output frequency in a selected one of said bands, said oscillator being voltage controlled within each of said bands, frequency divider means responsive to the oscillator frequency for frequency dividing the oscillator frequency and for deriving frequency divided output pulses having occurrence times determined by the selected channel, the spacing between adjacent ones of said output pulses being equal to the time required for the oscillator to derive a number of cycles equal to the frequency spread of each of said bands, means for gating only the output pulse having an occurrence time correlated with the preselected band, means for deriving a control voltage for the oscillator frequency in response to the time position of the gated output pulse, and means for controlling the oscillator frequency to the selected channel within the selected band in response to the control voltage.
Claim 13
Dependent Claim
189 words
A digital frequency synthesizer for deriving a predetermined one of a plurality of frequency channels within a frequency band, said synthesizer being capable of covering a number of said bands, comprising a voltage controlled oscillator settable to said bands, means for activating the oscillator so that it has an output frequency in a selected one of said bands, said oscillator being voltage controlled within each of said bands, frequency divider means responsive to the oscillator frequency for frequency dividing the oscillator frequency and for deriving frequency divided output pulses having occurrence times determined by the selected channel, the spacing between adjacent ones of said output pulses being equal to the time required for the oscillator to derive a number of cycles equal to the frequency spread of each of said bands, means for gating only the output pulse having an occurrence time correlated with the preselected band, means for deriving a control voltage for the oscillator frequency in response to the time position of the gated output pulse, and means for controlling the oscillator frequency to the selected channel within the selected band in response to the control voltage.
Claim 14
Dependent Claim
19 words
The digital frequency synthesizer of claim 10 wherein the frequency spread of each of said bands is the same.
Claim 15
Dependent Claim
32 words
The digital frequency synthesizer of claim 10 wherein said means for gating includes means for deriving a gating window having a length sufficient to pass not more than one frequency divided pulse.
Claim 16
Dependent Claim
24 words
The digital frequency synthesizer of claim 12 further including means for changing the length of the window in response to the selected frequency band.
Claim 17
Dependent Claim
23 words
The digital frequency synthesizer of claim 13 wherein said changing means includes means for effectively counting the number of cycles of the oscillator.
References Cited (Backward Citations)
US3753141A
Cited
US3713040A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |