US3753141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wide frequency range voltage controlled oscillator with crystal controlled frequency stabilizing loop
Assignee: US Philips Corp
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Filing: 1971-09-20
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Granted: 1973-08-14
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Expires: 1991-09-20
Abstract
Abstract A controllable broad-band frequency generator comprising a voltage-controlled oscillator incorporated in a frequency controlled loop and an external controllable voltage source connected thereto, the control loop furthermore incorporating a digital crystal stable frequency discriminator and a combination device in which the direct voltage value derived from the voltage source is deducted from the output voltage provided by the frequency discriminator to obtain a direct control voltage for frequency controlling the voltage-controlled oscillator.
Inventors
- 👤 Der Lee J Van
- 👤 A Morrien
- 👤 Elk C Van
- 👤 J Raaigever
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:03
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/02; H03C3/09; H03C3/0908; H03C3/0958; H03K; H03K7/00; H03K7/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
279 words
A controllable wide range frequency generator comprising a voltage-controlled oscillator, a control loop for stabilizing the output frequency of said voltage controlled oscillator, a crystal oscillator coupled to said control loop to provide reference signals, an external variable voltage source, means connecting said external voltage source to said voltage controlled oscillator to vary the stabilized output frequency of said oscillator over a large frequency range as a function of direct voltage from said external voltage source applied to said voltage controlled oscillator, said control loop comprising a frequency discriminator to produce signals representing deviations between the frequency of said voltage controlled oscillator and the frequency of said crystal oscillator, said frequency discriminator comprising a digital counter continuously counting the output pulses from one of the oscillators during consecutive counting cycles, means for producing gating signals from the output of the oscillator not supplying said digital counter to determine the duration of said consecutive counting cycles, and a digital-to-analog converter coupled to said digital counter to produce said frequency deviation signals at the end of each counting cycle, the magnitude and polarity of said frequency deviation signals corresponding to the magnitude and direction of the mean value of the deviation measured during said counting cycles of the frequency to be stabilized relative to a fixed discriminator center frequency characterized by a given counter content, a difference signal means coupled to the digital-toanalog converter of said frequency discriminator and said external voltage source to produce a signal corresponding to the difference between said frequency deviation signal and the direct voltage of said external voltage source, and means for integrating said difference signal to produce a frequency correction for said voltage-controlled oscillator.
Claim 2
Dependent Claim
279 words
A controllable wide range frequency generator comprising a voltage-controlled oscillator, a control loop for stabilizing the output frequency of said voltage controlled oscillator, a crystal oscillator coupled to said control loop to provide reference signals, an external variable voltage source, means connecting said external voltage source to said voltage controlled oscillator to vary the stabilized output frequency of said oscillator over a large frequency range as a function of direct voltage from said external voltage source applied to said voltage controlled oscillator, said control loop comprising a frequency discriminator to produce signals representing deviations between the frequency of said voltage controlled oscillator and the frequency of said crystal oscillator, said frequency discriminator comprising a digital counter continuously counting the output pulses from one of the oscillators during consecutive counting cycles, means for producing gating signals from the output of the oscillator not supplying said digital counter to determine the duration of said consecutive counting cycles, and a digital-to-analog converter coupled to said digital counter to produce said frequency deviation signals at the end of each counting cycle, the magnitude and polarity of said frequency deviation signals corresponding to the magnitude and direction of the mean value of the deviation measured during said counting cycles of the frequency to be stabilized relative to a fixed discriminator center frequency characterized by a given counter content, a difference signal means coupled to the digital-toanalog converter of said frequency discriminator and said external voltage source to produce a signal corresponding to the difference between said frequency deviation signal and the direct voltage of said external voltage source, and means for integrating said difference signal to produce a frequency correction for said voltage-controlled oscillator.
Claim 3
Dependent Claim
38 words
A frequency generator as claimed in claim 1, wherein said gating signal is generated with the aid of a frequency divider connected to the output of the voltage-controlled oscillator, the output pulses being derived from the crystal oscillator.
Claim 4
Dependent Claim
36 words
A frequency generator as claimed in claim 1, wherein said gating signal is generated with the aid of a frequency divider connected to the crystal oscillator output, the output pulses being derived from the voltage-controlled oscillator.
Claim 5
Dependent Claim
23 words
A frequency generator as claimed in claim 2, wherein the divisor of said divider is directly adjustable with the aid of decade switches.
Claim 6
Dependent Claim
29 words
A frequency generator as claimed in claim 3, wherein the divisor of said divider is adjustable with the aid of a read-only memory which is controlled by decade switches.
Claim 7
Dependent Claim
96 words
A frequency generator as claimed in claim 1, wherein said counter is constituted by a single counter which is started every time at the commencement of the counting cycle T from its maximum position characterizing the discriminator centre frequency, said counter counting down during the period of the counting cycle, the output pulses applied to the counter so as to determine a residual value which is representative of the mean value of the measured frequency deviation, said residual value being transferred after termination of the counting cycle to a buffer register connected to the digital-to-analog converter.
Claim 8
Dependent Claim
97 words
A frequency generator as claimed in claim 1, wherein said counter is constituted by two counters the first of which is started at the commencement of the counting cycle T from its zero position, which first counter upon reaching the value n (fo -Delta f/T) starts the second counter from the value n Delta f/T so as to determine a residual value which is representative of the measured frequency deviation relative to the discriminator centre frequency fo, said residual value being transferred after termination of the counting cycle to a buffer register connected to the digital-to-analog converter.
Claim 9
Dependent Claim
18 words
A frequency generator as claimed in claim 7, wherein said first counter is formed as an adjustable divider.
Claim 10
Dependent Claim
84 words
A frequency generator is claimed in claim 1, further comprising a time corrector to which both the gating signal and the output pulses are applied, said corrector being responsive output to said pulses and gating signals to produce control pulses which are applied to said counter and to a buffer register so as to control the transfer of said residual value which is representative of the measured frequency deviation relative to the discriminator center frequency and to reset said counter to its initial position.
Claim 11
Dependent Claim
60 words
A frequency generator as claimed in Claim 9, wherein said time corrector comprises an auxiliary counter which is rendered active for a given short period at the commencement of the counting cycle so as to generate said control pulses for transferring the residual value from said counter to said buffer register and for resetting said counter to its initial position.
References Cited (Backward Citations)
US3651422A
Cited
US3644840A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |