GB2147167A - Temperature-compensated oscillator - Google Patents
Temperature-compensated oscillator Download PDFInfo
- Publication number
- GB2147167A GB2147167A GB08418087A GB8418087A GB2147167A GB 2147167 A GB2147167 A GB 2147167A GB 08418087 A GB08418087 A GB 08418087A GB 8418087 A GB8418087 A GB 8418087A GB 2147167 A GB2147167 A GB 2147167A
- Authority
- GB
- United Kingdom
- Prior art keywords
- temperature
- resistor
- sensitive element
- sensitive
- circuit
- 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.)
- Withdrawn
Links
- 239000010453 quartz Substances 0.000 claims abstract description 19
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 19
- 238000010586 diagram Methods 0.000 description 7
- 230000003247 decreasing effect Effects 0.000 description 5
- 229910052729 chemical element Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 1
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
- H03L1/022—Stabilisation of generator output against variations of physical values, e.g. power supply against variations of temperature only by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature
- H03L1/023—Stabilisation of generator output against variations of physical values, e.g. power supply against variations of temperature only by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature by using voltage variable capacitance diodes
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- Oscillators With Electromechanical Resonators (AREA)
Abstract
A temperature-compensated oscillator comprises first and second temperature-sensitive elements (22, 23) connected in series between power supply terminals (20, 21), a series circuit comprised of a resistor (24) and third temperature-sensitive element (25) which series circuit is connected in parallel with the second temperature-sensitive element, and an oscillator circuit comprised of a series circuit of a quartz resonator (30) and variable capacity diode (29), in which a compensating voltage across the third temperature-sensitive element is applied to the variable capacity diode to control the oscillating frequency of the oscillating circuit. <IMAGE>
Description
SPECIFICATION
Temperature-compensated oscillator
This invention relates to a highly stable, temperature-compensated quartz oscillator for compensating for a frequency variation due to the temperature ofthe oscillator.
Generally,thefrequency of a resonant element such as in a quartz resonator will vary depending upon the temperature thereof. This is called a frequencytemepature characteristic. Such an oscillator is of a temperature compensating type which cancels the frequency variation in accordance with on the frequency-temperature characteristic, and due to the temperature variation thereof.
Fig. 1 shows a schematic block diagram which, is known as a conventional temperature compensating oscillator. In the circuit as shown in Fig. 1, reference numeral 1 shows an AT-cut quartz resonator having a frequency-temperature characteristic as indicated by, for example, the cubic curve in Fig. 2; and reference numeral 2 shows an oscillator circuitfor oscillating quartz resonator. Reference numeral 3 shows a variable capacity diode in series with the quartz resonator 1. Referencenumeral4showsatempera- ture compensating circuit adapted to produce a compensating voltage for compensating for an oscillation frequency variation of the quartz resonator 1 according to the frequency-temperature characteristic. The compensating voltage on the temperature compensating circuit4 is applied through a resistor 5 to the variable capacity diode 3.It should be noted that the compensating voltage needs to compensate for a variation oftheoscillating frequency dueto the temperature ofthe quartz oscillator. The frequencytemperature characteristic of the quartz resonator 1 takes a cubic curve with extreme values X and Yas shown,for example, in Fig. 2. A complex circuit arrangement is necessary to in making the frequencytemperature characteristic flat.
Fig. 3 is a block diagram showing one form of a conventional temperature compensating circuit for compensating for a cubic curve type frequencytemperature characteristic. An input voltage Vi between powersupplyterminals 6and 7 isappliedto a series circuit of the first and second temperaturesensitive elements 8 and 9 whose resistive values vary depending upon the ambient temperature. Athird temperature-sensitive elements loins connected in parallel with the second temperature-sensitive elements 9, and has outputterminals 11 and 12. A compensating voltage Vo across the of itpUtteFFninals~ 11 and 12 is applied to thevariable capacity diode 3, -- for example, in Fig. 1.
Thevariablecapacitydiode 3 has its capacityvaried corresponding to the voltage across the output terminals 11 and 12. The capacity ofthe variable capacity diode 3 is decreased with an increase in the level ofthevoltage applied, and thus the oscillating frequency shifts to a higher frequency level. When, on the other hand, the applied voltage is descreased, the capacity of the variable capacity diode 3 is increased, and thus the oscillating frequency shifts to lower frequency level
Fig. 4 is a detailed diagram showing the respective
temperature-sensitive elements 8,9 and 10 in Fig. 3.
The firsttemperature-sensitive element 8 comprises a
series combination of a resistor 15 and the parallel
circuit of a resistor 13 along with a thermistor 14. The
second temperature-sensitive element 9 comprises a
series circuit of a resistor 16 and thermistor 17; and the
third temperature-sensitive element 10 comprises a
parallel circuit of a resistor 18 and thermistor 19.
The first temperature-sensitive element 8 causes
the compensating voltage Vo to vary mainly over a rangefrom the extreme value X to the extreme value Y
corresponding to a midrange of the frequency
temperature characteristic curve. Similarly, the
second temperature-sensitive element 9 causes the
compensating voltage Vo to vary mainly over a range
below the extreme value X; and the third temperature
sensitive element 10 causesthe compensating voltage Vo to vary mainly over a range above the extreme
value Y. In these ways, the frequencyvariation is
compensated for.
Viewed from the output terminals 11 and 12, the first
temperature-sensitive element 8 connected in series
between the power supply terminal 6 and the output terminal 11 causes the compensating voltage Vo to be
increased with a rise in the temperature thereof which
corresponds to the negative change rate ofthe frequency between the extremevalues X and Yofthe quartz resonator. Similarly, the second and third temperature-sensitive elements 9 and 10 connected in
parallel between the output terminals 11 and 12
causes the compensating temperature Vo to be
decreased with a rise in the temperature thereof which
corresponds to the negative change rate of the frequency over the two temperature ranges, one of
which is lowerthan the extreme value X and the other
of which is higher than the extreme value Y.
The change of the resistive value of the temperature-sensitive element 8 becomes dominant in the
midrange between the extreme values X and Y on the
frequency-temperature characteristic curve, while the
change of the resistive value ofthe second temperature-sensitive element 8 becomes dominant over the
range lowerthantheextremevalueX.
Over the temperature midrange between the extremevalues X and Yin Fig. 3, the resistive value R(3) ofthethirdtemperature-sensitive element 10 is set to
be much greaterthanthe resistive value R(2) of the
second temperature-sensitive element 9, that is, it is
set to satisfy R(3) > > R(2). In Fig. 4the resistive value
r(16) ofthe resistor 16 issetto be much greaterthan the resistivevalueTH(17) ofthethermistor 17, i.e., r(16) > > TH(17). Overthetemperature midrange,
See, the variation of the first temperature- sensitive ele Ibflt becomes dominant with respect to the compensating voltage Vo.
Overthetemperature range lowerthan the extreme value X, the resistive value R(3) of the third temper aturedsensitive element 10 in Fig. 3 is set to be much greaterthanthe resistive value R(2) of the second temperature-sensitive element 9, i.e., it is set to satisfy
R(3) > > R(2).In Fig. 4, the resistive value r(3) of the resistor 13 is set to be much smaller than the resistive valueTH(1 4) ofthe thermistor 14, i.e., it is setto obtain r(l30 (( To(14). Over the lower temperature range,
therefore, the variation of the second temperature
sensitive element9 becomes dominantwith respect to
the compensating voltage Vo.
Even if a resistive value r(16) of the resistor 16 is set
to be much greaterthan a resistive value TH(17) of the thermistor 17 (i.e., r(16) > > TH(17)) in orderto cause the temperature compensation to be made over the
temperature range higher than the extreme value V, it
would be difficultto obtain the relation: r(16) > > R(3).
The rate of change ofthe resistive value with respect
to the temperature of the third temperature-sensitive
element 10 is so greatly affected by the resistor 16 that
the rate of change of the resistive value with respect to
the temperature variation of the third temperature
sensitive element 10 will be decreased. From this, it
follows that a desired temperature compensation
voltage characteristic to be obtained overthetemper- ature range higherthan the extreme value V is very
greatly affected by the second temperature-sensitive
element 9.Thethird temperature-sensitive element 10 which serves to decrease the compensating voltage
Vo with the rise in the temperature thereof is
influenced by the first temperature-sensitive element
8 which acts to increase the compensation voltage Vo.
It is therefore necessary that in orderto effect a
temperature compensation over the temperature
range higherthanthe extreme value V, the resistance
temperature coefficient (usually referred to as a B constant) of thethermistor 19 must be appreciably
greater than those of the thermistors 14 and 17.
The conventional temperature compensation circuit
of Fig.4 can provide a desired compensating voltage
Vo for a cubic curve by accurately selecting the
parameters and values of the thermistors 14, 17 and 19
and resistors 15,13, 16 and 18 of the first, second and
third temperature-sensitive elements 8,9 and 10,
respectively.Since the temperature-sensitive ele ments 8,9 and 10 suffer a mutual interference,the resistive values and resistance temperature coeffi
cients of the respective thermistors 14,17 and 19 are
restricted in an attemptto obtain a desired compen
sating voltageVo. It is, therefore, next to impossible to
obtain a desired compensation voltage characteristic
especially over the high temperature range. As the
temperature-sensitive resistors, use may be made not
only of a thermistor with a negative temperature
coefficient but also of a semi-conductortemperature- sensitive resistor with a positive temperature coeffi
cient, butthese elements are undesirably aged out of
date.
It is accordingly the object ofthis invention to
provide a temperature-compensated oscillator which
can readily provide a temperature compensation to a
quartz oscillator using a quartzrnsonatorbaviflg frequency-temperature characteristic of cubic curve ndtaet a esired temperature compensation
characteristic over a range higherthan an extreme
value especially atthe high temperature side of the
cubic curve.
According to this invention there is provided a
temperature-compensated oscillator which can pre
cisely and readily obtain a desiredtemperature compensation characteristic of a cubic curve over a
temperature range, especially a high temperature
range, of a quartz resonator.
According to this invention there is provided an
temperatu re-compensated oscillator comprising
powersupplyterminals connected to receive a DC
voltage; first and second temperature-sensitive ele
ments connected in series between the powersupply
terminals; a seriescircuit of a resistor and third tem perature-sensitive element which is connected in
parallel to the secondtemperature-sensitive element;
a variable capacity diode connected in series to a
quartz resonatorto causeavoltage across the third
temperature-sensitive element to be applied thereto
as a compensating voltage; and an oscillator circuit
comprised of the quartz resonator and variable
capacity diode.
This invention can be morefully understood from
the following detaileddescription when taken in
conjunction with the accompanying drawings, in
which:
Fig. is a schematic block diagram having one form
of a temperature-compensated oscillator;
Fig. 2 is a graph showing one example ofthe temperature-frequency characteristic of a quartz re
sonator;
Fig. 3 is a block diagram having one form of a
conventional temperature compensating circuit;
Fig. 4 is a block diagram showing a conventional
temperature-compensated oscillatorwith details of
temperature-sensitive elements in the temperature
compensating circuit of Fig. 3; Fig. 5 is a block diagram showing a temperature
compensating oscillator according to one embodi ment ofthis invention;;
Fig. 6 is a graph showing a variation of a compensat
ing voltage ofthe oscillator in Fig. 5; and
Fig. 7 is a view showing a variation characteristic of
a compensating voltage to the temperature ofthe temperature-compensated oscillator of Fig. 5.
Atemperature-compensated oscillator according
to one embodiment of this invention will be explained
below by referring to the accompanying drawings.
Fig.5 is a blockdiagram showing atemperature compensated oscillator according to one embodi
mentofthis invention. In Fig. 5, reference numerals 20 and show powersupplyterminals to which a stabilized DCvoltageVi is supplied from a power
supply (not shown).Between the power supply
terminals 20 and 21 isaseries circuit offirst and second temperature-sensitive elements 22 and 23
whose resistivevaluesvary depending upon the ambienttemperature Thefirsttem perature-sensitive
element 22 senses the temperature mainly overthe midrange of a tem recharacteristic of a cubic ncyna7dasefind temperature-sensitive element 23 senses the temperature mainly over the low-tern per
ature region thereofAcrnss the second temperature- sensitive element 23 are connected a series circuit of
a resistor 24 and athirdtemperature-sensitive
element 25 which senses thetemperature principally over a high temperature region thereof. A veltage on thethird temperatures-sensitive element 25 is deli vered as a compensating voltage through output
terminals 26 and 27. The compensating voltage is
applied through a resistor 28 to a variable capacity
dode 29to control the electorstatic capacity ofthe diode 29. The variablecapacity diode 29 is connected in series to a quartz resonator 30 which is, in turn, connected in series to an oscillator circuit 31.
Atemperature compensating circuit as indicated bythe box-shape in Fig. 5 comprises a resistor 24 and first, second and third temperature-sensitive elements 22,23 and 25. In Fig. 5, the first, second and thirdtemperature-sensitive elements 22,23 and 25 are similar in arrangement and operation to the arrangement of the corresponding elements as shown in Fig. 4. In the temperature compensating circuit as shown in Fig. 5,the resistor 24 is connected between the second and third temperature-sensitive elements 23 and 25. With r(24) representing a resistive value of the resistor 24, the compensating voltageVo in Fig. 5 is given by: Vo = Vi ##############################################
.... (A) Where the resistive values of the first, second, and third temperature-sensitive elements denote R(1),
R(2) and R(3), respectively.The compensating voltage Vo of the conventional temperature compensating circuit as shown in Fig. 3 can be expressed below: Vo = Vi ##############################
..... (B) Upon comparison, Equation (A) is different from
Equation (B) in that theterm r(24){R(1)1 R(2)} is added to the denominator of Equation (A). If{(R(1)+R(2)} # 1 overthe desired range, then the compensating voltage Vo in Equation (A) is lowerthanthecompen- sating voltage Vo in Equation (B) overthedesired temperature range.Thefirst,second and third temperature-sensitiveelements22, 23 and 25 have their negative resistance temperature characteristics.
With an increasing temperature, the effect ofthe term r(24)(R(1)+R(2)} upon the compensating voltage Vo becomes prominent and thus the compensating voltage Vo is greatly decreased.
Atemperature,which represents an extreme value on the high ternperature side of the compensating voltage Vo with respectto the temperature in Fig. 6, can be varied in accordance with a resistive value r(24) of the resistor 24 in Fig. 5.
In the conventional temperature compensating circuit as shown in Fig. 3, the resistive value r(24) of the resistor 24 in Fig. 5 corresponds to the case where it is equal to zero, and the temperature representing the extremevalue is shifted to a lowtemperaturewith an increase in the resistive value r(24).
Fig. 7 shows a temperature characteristic curve withthevalue r(24) ofthe resistor24obtained by multiplying a specific resistive value r(24) = Ro( > > O) by a coefficient as a parameter, noting that the respective temperature-sensitive elements 22,23 and 25 inthe temperature compensating circuit in Fig. 5 ate teach comprised of a resistor and thermistor as shown in Fig. 4. From this it will be seen that, in the circuit arrangement corresponding to the conventional temperature compensating circuit in Fig. 3, that is, as in the case of r(24) = O, no extreme value is reached at a high temperature even at a temperature of 90 C.With an increase of the resistive value r(24) to 0.20Ro, 0.5Ro, 0.90Ro . . ., the temperature representing the extreme value is decreased to 77 C, 65 C, 60 C,
..,respectively.
The proper choice of the resistive value r(24) permits a shift of the extreme value from a high to a lowtemperature of the characteristic curve. As a result, the voltage characteristic ofthe temperature compensating circuit with respect to the temperature can take a cubic curve over the desired temperature range.
The proper selection of the amount of variation of the resistive value with respect to the temperature variation of the temperature-sensitive element permits a variation in AVo/At, a gradient of the temperature voltage characteristic especially over a high temperature range. Thus, a wide freedom of design which permits a temperature voltage characteristic overthattemperature range is made possible.
Claims (6)
1. Atemperature-compensated oscillatorcom- prising power supply terminals connected to receive a DC voltage; the first and second temperature- sensitive elements connected in series between said power supply terminals; a series circuit of a resistor and the third temperature-sensitive element which is connected in parallel to said second temperaturesensitive element; a variable capacity diode connected in seriesto a quartz resonatorto cause a voltage across the third temperature-sensitive elementto be applied thereto as a compensating voltage; and an oscillator circuit comprised of said quartz resonator and variable capacity diode.
2. Atemperature-compensated oscillator of claim 1, in which said quartz resonator has a frequencytemperature characteristic of a cubic curve; said first temperature-sensitive element performs temperature compensating control over a middle temperature range between adjacent extreme values of said cubic curve; said second temperature-sensitive element performs temperature compensating control over a temperature range lowerthan one of said extreme values which is on the lowtemperature side; and said third temperature-sensitive element performs compensating control over a temperature rangehigherthan one of said extreme values which is on the high temperature side.
3. A temperature-compensated oscillator of claim 1, in which said first, second and third temperaturecompensating elements each comprise a thermistor and resistor.
4. Atemperature-compensated oscillator of claim 1, in which said first temperature-sensitive element comprises a series circuit of a resistor and parallel circuit of a thermistor and resistor; said second temperature-sensitive element comprises a series circuit of a thermistor and resistor; and said third temperature-sensitive element comprises a parallel circuit of a thermistor and resistor.
5. A temperature-compensated oscillator of claim 1, in which the temperature of one of adjacent extreme values which is on a high temperature side is set according to the value of a resistor between the second and third temperature-sensitive elements.
6. Atemperature-compensated oscillator, substantially as hereinbefore described with reference to
Figs. 1,2,5,6 and 7 ofthe accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13097983A JPS6024704A (en) | 1983-07-20 | 1983-07-20 | Temperature compensating oscillator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8418087D0 GB8418087D0 (en) | 1984-08-22 |
| GB2147167A true GB2147167A (en) | 1985-05-01 |
Family
ID=15047072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08418087A Withdrawn GB2147167A (en) | 1983-07-20 | 1984-07-16 | Temperature-compensated oscillator |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS6024704A (en) |
| DE (1) | DE3426645A1 (en) |
| FR (1) | FR2549656B1 (en) |
| GB (1) | GB2147167A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5004988A (en) * | 1988-07-25 | 1991-04-02 | Nihon Dempa Kogyo Co., Ltd. | Quartz crystal oscillator with temperature-compensated frequency characteristics |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0718897B2 (en) * | 1986-05-28 | 1995-03-06 | セイコ−電子部品株式会社 | Frequency temperature compensation circuit for crystal oscillator |
| CN103680456B (en) * | 2013-12-29 | 2016-10-05 | 京东方科技集团股份有限公司 | A kind of 3D liquid crystal panel gray-scale intensity control method and device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1238762A (en) * | 1969-04-25 | 1971-07-07 |
-
1983
- 1983-07-20 JP JP13097983A patent/JPS6024704A/en active Pending
-
1984
- 1984-07-16 GB GB08418087A patent/GB2147167A/en not_active Withdrawn
- 1984-07-19 FR FR8411481A patent/FR2549656B1/en not_active Expired - Fee Related
- 1984-07-19 DE DE19843426645 patent/DE3426645A1/en not_active Ceased
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1238762A (en) * | 1969-04-25 | 1971-07-07 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5004988A (en) * | 1988-07-25 | 1991-04-02 | Nihon Dempa Kogyo Co., Ltd. | Quartz crystal oscillator with temperature-compensated frequency characteristics |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3426645A1 (en) | 1985-02-07 |
| JPS6024704A (en) | 1985-02-07 |
| GB8418087D0 (en) | 1984-08-22 |
| FR2549656B1 (en) | 1990-11-30 |
| FR2549656A1 (en) | 1985-01-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |