US3287658A - Frequency standard - Google Patents
Frequency standard Download PDFInfo
- Publication number
- US3287658A US3287658A US173199A US17319962A US3287658A US 3287658 A US3287658 A US 3287658A US 173199 A US173199 A US 173199A US 17319962 A US17319962 A US 17319962A US 3287658 A US3287658 A US 3287658A
- Authority
- US
- United States
- Prior art keywords
- oven
- amplifier
- oscillator
- temperature
- controller
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000013078 crystal Substances 0.000 claims description 22
- 230000000087 stabilizing effect Effects 0.000 claims description 4
- 230000010355 oscillation Effects 0.000 description 6
- 238000004804 winding Methods 0.000 description 6
- 230000003321 amplification Effects 0.000 description 4
- 238000003199 nucleic acid amplification method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000003534 oscillatory effect Effects 0.000 description 1
- 230000002277 temperature effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L1/00—Stabilisation of generator output against variations of physical values, e.g. power supply
- H03L1/02—Stabilisation of generator output against variations of physical values, e.g. power supply against variations of temperature only
- H03L1/04—Constructional details for maintaining temperature constant
Definitions
- the present invention relates to frequency standards and more particularly to a highly stable crystal controlled frequency standard.
- a crystal controlled oscillator having a very high degree of frequency stability over relatively extended periods of time and in the presence of relatively large changes in load, and ambient temperature.
- the principles which have permitted the development of an apparatus having the desired performance characteristics relate to the utilization of two, proportionally controlled ovens in which the oscillator circuit and crystal are located in an inner oven, the inner oven temperature controller and other temperature sensitive elements of the apparatus are located in an outer oven.
- an AVC transistorized amplifier employed to provide an AVC voltage to the oscillator circuit, this amplifier also employing internal negative feedback to stabilize gain and increase input impedance.
- the proportional controller for the outer oven may be identical with the one for the inner oven and continuing the above example is able to maintain the outer oven temperature variations at less than 1 over a 70 change in ambient temperature.
- the inner oven being controlled to maintain temperature variations of roughly %00 of those in the outer oven, the changes in temperature in the inner oven, in which the exceedingly temperature sensitive elements are located, are less than of a degree over a 70 change in ambient temperature. This extreme temperature control is efiected even though the oven controllers are relatively conventional in form and inexpensive.
- a second feature of the apparatus relates to the utilization of a transistorized video amplifier to provide the AVG signal for maintaining a constant level of oscillator output signal.
- a transistorized video amplifier By employing an internal negative feedback loop in the video amplifier the gain of the video amplifier is stabilized to a high degree so that the AVG voltage is primarily a function of oscillator output signal uncomplicated by changes due to variations in gain of the video amplifier.
- the video amplifier provides a high input impedance which is increased and stabilized by the use of negative feedback and therefore the oscillator load is maintained at a fixed high impedance value.
- the video amplifier is also located within the outer oven and consequently is subject to only very small temperature changes.
- An oscillator employing the principles of the present invention has been built which is'designed to supply a 50 ohm load. Variations of plus or minus 20% in the value of the resistance of the load produce a change in frequency relative to the frequency for which the apparatus is tuned of i2 10- The same device exhibited a change in frequency relative to the output frequency of :5Xl0 in the presence of temperature changes of C. relative to a basic temperature of 25 C.
- the apparatus of the present invention is intended to provide an extremely stable crystal controlled device and as will become apparent upon subsequent description, the apparatus is relatively simple in construction, quite compact and extremely rugged. Relative to the compactness, the device to be described is contained in a cylinder four inches in diameter and six inches long.
- FIGURE 1 is a schematic block diagram of the basic oscillator of the present invention.
- FIGURE 2 is a partial schematic circuit, partial block diagram of the temperature controller employed in the present invention.
- a first or inner oven 1 located internally of a second or outer oven 2.
- the oven 1 is a hollow cylinder having removable end walls and a heater winding 3 wound helically about the outer circumference thereof.
- the outer oven 2 is cylindrical and has a helically wound heater 4 disposed about its outer circumference.
- an oscillator 6 the frequency of oscillation of which is stabilized by a crystal 7.
- the crystal controlled oscillator 6 may be, for purposes of illustration only a modified Pierce type oscillator, although the specific type of oscillator is notcrit-ical to the invention.
- the video amplifier 9 is also provided with a negative feedback loop generally designated by the reference numeral 13 which is employed to stabilize the gain of the video amplifier 9.
- the gain of the amplifier 9 is initially maintained within relatively narrow limits by placing the video amplifier inside of the outer oven 2 so that the amplifier is not subject to extreme temperature variations. This initial stability is further enhanced by employing negative feedback through the loop 13 so that the amplifier 9 is substantially a constant gain device. Further, since a video type amplifier is employed, the input impedance to the amplifier is quite high. If a transistorized amplifier is employed, this providing several advantages such as size, cost and dependability, then the negative feedback increases the input impedance and stabilizes it along with the gain of the amplifier.
- the above arrangement provides two distinct and important advantages in the operation of the apparatus.
- the fixed high input impedance to the video amplifier 9 maintains a constant load on the crystal 7 which is essential to the high stability of the output frequency.
- the AVG voltage appearing on the lead 12 refiects changes intern-ally of the oscillator 6 only and does not reflect to any appreciable extent changes in characteristics of the video amplifier 9.
- the inner and outer ovens 1 and 2 are controlled by identical oven controllers designated respectively by the reference numerals 14 and 16.
- the inner oven has located therein a thermistor 17 serving as the sensing element for the controller 14.
- the power output signal of the controller 14 drives a heater 3, directly.
- the controller 14 is a proportional control device as is the controller 16 so that a very high degree of temperature regulation is possible.
- the outer oven controller 16 employs a thermistor 18 as its sensing element and the output energy from the controller 16 is employed to 'drive the heater 4.
- the controller 14 includes a resistance bridge for detecting changes in impedance in the thermistor element.
- the resistors employed in the bridge are chosen for their temperature stability and thus the input signal to the amplifier section of the controller is, for all practical purposes, a function only of the changes in temperature of the inner oven.
- the temperature stability in the outer oven also stabilizes the gain of the amplifier section of the controller 14 so that the overall effect of this arrangement is to provide extremely high temperature stability in the inner oven in which are located only these elements which are extremely sensitive to temperature variations.
- the controller comprises a three stage amplifier employing positive feedback.
- the feedback produces oscillation of the circuit and the amplitude of the oscillation is a function of the degree of unbalance of the bridge.
- the three stage amplifier employed in the apparatus comprises a first stage of amplification including NPN transistor 19, a second stage of amplification including the NPN transistor 21 and a third stage of amplification including the NPN transistor 22.
- a primary winding 23 of a transformer 24 is connected in the collector circuit of the transistor 22 as its load.
- Transformer 24 has a center-tapped secondary winding 26 and connected across the secondary winding is a variable resistor 27, a fixed resistor 28 and the thermistor 18 if this is the inner oven controller and thermistor 18 if it is the outer oven controller.
- the output voltage of the bridge is taken between leads 29 and 31, the former being connected to the center tap of the secondary winding 26 and the latter being connected between resistor 28 and thermistor 18 or 17.
- the lead 31 is returned to the base electrode of the transistor 19 to provide a positive feedback loop to the input of the three stage amplifier.
- Operating voltage for the circuit is derived from a bus 32 and a second bus 34 is connected to a suitable source of refer ence potential, such as ground.
- the output signal of the amplifier is developed at the collector of the transistor 22 and is applied to an output terminal 33. After suitable amplification this signal is employed to drive the heater 3 or 4 as the case may be.
- the temperature controller is of completely conventional operation and it is to be seen that it requires a threestage amplifier and a bridge circuit with a feedback from the bridgeto the amplifier so as to produce oscillation upon imbalance of the bridge.
- the .same controller is employed for both ovens and the novelty in the temperature control does not reside primarily in the circuit but in the utilization of two proportional controllers for two related ovens in which the inner oven controller is located in the outer oven.
- the AVC video amplifier is also of conventional design.
- the AVC voltage is derived through a rectifier-filter arrangement coupled to a signal circuit of the amplifier so as to derive the negative voltage required to stabilize the oscillator output signal.
- the negative feedback voltage for the video amplifier is derived directly from the output voltage of the amplifier and is applied to the emitter electrode of a common emitter connected transistor serving as the input stage of the amplifier.
- a frequency standard comprising a temperature stabilized outer oven, a temperature stabilized inner oven located in said outer oven, a crystal controlled oscillator located in said inner oven, a high input impedance amplifier for amplifying output Waves generated by said oscillator, said amplifier being located in said outer oven and including negative feedback means for stabilizing its gain, means responsive to the output of said amplifier for deriving an automatic volume control signal indicative only of the amplitude of said waves as derived from said amplifier, and means responsive to said automatic volume control signal to stabilize the amplitude of the output waves generated by said oscillator.
- a frequency standard comprising an outer oven, an inner oven, an oscillator, a piezoelectric crystal connected to said oscillator to stabilize the oscillatory frequency of said oscillator, said oscillator and crystal being located in said inner oven, means including a temperature sensitive element for deriving a first signal indicative of the deviation of the temperature of said inner oven from a desired temperature, means responsive to said first signal for stabilizing the temperature of said inner oven at said desired temperature, said means for deriving, exclusive of said temperature sensitive element, being located in said outer oven, means including a temperature sensitive element for deriving a second signal indicative of the deviation of the temperature of said outer oven from a desired temperature, means responsive to said second signal for stabilizing the temperature of said outer oven at said desired temperature, a transistorized amplifier having a high input impedance and including a negative feedback circuit to stabilize its gain and increase and stabilize its input impedance, said amplifier being located in said outer oven, means conmeeting said amplifier to receive the output waves generated by said oscillator, mean-s for deriving an automatic gain
Landscapes
- Oscillators With Electromechanical Resonators (AREA)
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Description
Claims (1)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US173199A US3287658A (en) | 1962-02-14 | 1962-02-14 | Frequency standard |
GB18059/62A GB1010818A (en) | 1962-02-14 | 1962-05-10 | Frequency standard |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US173199A US3287658A (en) | 1962-02-14 | 1962-02-14 | Frequency standard |
Publications (1)
Publication Number | Publication Date |
---|---|
US3287658A true US3287658A (en) | 1966-11-22 |
Family
ID=22630943
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US173199A Expired - Lifetime US3287658A (en) | 1962-02-14 | 1962-02-14 | Frequency standard |
Country Status (2)
Country | Link |
---|---|
US (1) | US3287658A (en) |
GB (1) | GB1010818A (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3619806A (en) * | 1969-11-21 | 1971-11-09 | Us Navy | Temperature-controlled crystal oscillator |
US3668527A (en) * | 1968-12-23 | 1972-06-06 | Us Navy | Crystal oscillator for satellite |
US3697886A (en) * | 1971-11-08 | 1972-10-10 | Us Navy | Solid state radio frequency voltage controlled oscillator, power amplifier and direct current power supply |
US4048580A (en) * | 1976-10-18 | 1977-09-13 | The United States Of America As Represented By The Secretary Of The Army | Apparatus for detecting a stable microwave discrete frequency |
US5467059A (en) * | 1993-01-29 | 1995-11-14 | Siemens Aktiengesellschaft | Temperature-stabilized oscillator circuit having heating elements that can be externally influenced |
US5798502A (en) * | 1996-05-10 | 1998-08-25 | Oak Frequency | Temperature controlled substrate for VLSI construction having minimal parasitic feedback |
US6621361B1 (en) * | 2000-10-17 | 2003-09-16 | Cts Corporation | Dual oven oscillator using a thermoelectric module |
EP1715577A2 (en) * | 2005-04-11 | 2006-10-25 | Epson Toyocom Corporation | High-stability piezoelectric oscillator |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2170930B (en) * | 1985-02-07 | 1988-10-05 | Sherritt Gordon Mines Ltd | Quadrupole mass spectrometers |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1959156A (en) * | 1933-04-18 | 1934-05-15 | Gen Electric | Electron discharge system |
US2169307A (en) * | 1935-06-15 | 1939-08-15 | Rca Corp | Low-loss circuit apparatus |
US2775699A (en) * | 1954-08-03 | 1956-12-25 | Bell Telephone Labor Inc | Crystal oscillator apparatus |
US3007023A (en) * | 1958-03-05 | 1961-10-31 | Amphenol Borg Electronics Corp | Temperature control device for a frequency standard generator |
US3084294A (en) * | 1959-01-08 | 1963-04-02 | Lucio M Vallese | Stabilized oscillator power source with feedback diode capacitance controls |
US3109082A (en) * | 1961-06-01 | 1963-10-29 | Avco Corp | Electronic clock |
-
1962
- 1962-02-14 US US173199A patent/US3287658A/en not_active Expired - Lifetime
- 1962-05-10 GB GB18059/62A patent/GB1010818A/en not_active Expired
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1959156A (en) * | 1933-04-18 | 1934-05-15 | Gen Electric | Electron discharge system |
US2169307A (en) * | 1935-06-15 | 1939-08-15 | Rca Corp | Low-loss circuit apparatus |
US2775699A (en) * | 1954-08-03 | 1956-12-25 | Bell Telephone Labor Inc | Crystal oscillator apparatus |
US3007023A (en) * | 1958-03-05 | 1961-10-31 | Amphenol Borg Electronics Corp | Temperature control device for a frequency standard generator |
US3084294A (en) * | 1959-01-08 | 1963-04-02 | Lucio M Vallese | Stabilized oscillator power source with feedback diode capacitance controls |
US3109082A (en) * | 1961-06-01 | 1963-10-29 | Avco Corp | Electronic clock |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3668527A (en) * | 1968-12-23 | 1972-06-06 | Us Navy | Crystal oscillator for satellite |
US3619806A (en) * | 1969-11-21 | 1971-11-09 | Us Navy | Temperature-controlled crystal oscillator |
US3697886A (en) * | 1971-11-08 | 1972-10-10 | Us Navy | Solid state radio frequency voltage controlled oscillator, power amplifier and direct current power supply |
US4048580A (en) * | 1976-10-18 | 1977-09-13 | The United States Of America As Represented By The Secretary Of The Army | Apparatus for detecting a stable microwave discrete frequency |
US5467059A (en) * | 1993-01-29 | 1995-11-14 | Siemens Aktiengesellschaft | Temperature-stabilized oscillator circuit having heating elements that can be externally influenced |
US5798502A (en) * | 1996-05-10 | 1998-08-25 | Oak Frequency | Temperature controlled substrate for VLSI construction having minimal parasitic feedback |
US6621361B1 (en) * | 2000-10-17 | 2003-09-16 | Cts Corporation | Dual oven oscillator using a thermoelectric module |
EP1715577A2 (en) * | 2005-04-11 | 2006-10-25 | Epson Toyocom Corporation | High-stability piezoelectric oscillator |
US20060237426A1 (en) * | 2005-04-11 | 2006-10-26 | Epson Toyocom Corporation | High-stability piezoelectric oscillator |
EP1715577A3 (en) * | 2005-04-11 | 2007-01-17 | Epson Toyocom Corporation | High-stability piezoelectric oscillator |
US7427902B2 (en) | 2005-04-11 | 2008-09-23 | Epson Toyocom Corporation | High-stability piezoelectric oscillator |
Also Published As
Publication number | Publication date |
---|---|
GB1010818A (en) | 1965-11-24 |
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Date | Code | Title | Description |
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AS | Assignment |
Owner name: TRACOR HYDRONAUTICS Free format text: CHANGE OF NAME;ASSIGNOR:T-HYDRONAUTICS, INC.;REEL/FRAME:004186/0077 Effective date: 19830429 |
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AS | Assignment |
Owner name: TRACOR AEROSPACE AUSTIN INC Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:TRACOR INC A TX CORP;REEL/FRAME:004188/0864 Effective date: 19830901 |
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AS | Assignment |
Owner name: TORONTO-DOMINION BANK, THE, AS AGENT Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR, INC.;REEL/FRAME:004810/0283 Effective date: 19871216 Owner name: TORONTO-DOMINION BANK, THE, AS AGENT Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR, INC.,;REEL/FRAME:004810/0246 Effective date: 19871216 |
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AS | Assignment |
Owner name: BANK OF AMERICA AS AGENT Free format text: SECURITY INTEREST;ASSIGNOR:TORONTO-DOMINION BANK, THE;REEL/FRAME:005197/0122 Effective date: 19880801 Owner name: TORONTO-DOMINION BANK, THE Free format text: SECURITY INTEREST;ASSIGNORS:TRACOR, INC.;LITTLEFUSE, INC.;TRACOR AEROSPACE, INC.;AND OTHERS;REEL/FRAME:005234/0127 Effective date: 19880801 Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIA Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR, INC.;REEL/FRAME:005217/0247 Effective date: 19880801 Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIA Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR INC.;REEL/FRAME:005217/0224 Effective date: 19880801 Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIA Free format text: SECURITY INTEREST;ASSIGNOR:TORONTO-DOMINION BANK THE;REEL/FRAME:005224/0751 Effective date: 19880801 Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIA Free format text: SECURITY INTEREST;ASSIGNORS:TORONTO-DOMINION BANK;TRACOR, INC.;REEL/FRAME:005224/0276 Effective date: 19880801 |
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AS | Assignment |
Owner name: TRACOR, INC. Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION AS COLLATERAL AGENT;REEL/FRAME:005957/0562 Effective date: 19911220 Owner name: TRACOR, INC. Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION AS COLLATERAL AGENT;REEL/FRAME:005957/0542 Effective date: 19911227 |