DE1762746A1 - Method for syntonizing precise oscillators and the arrangement for performing this method - Google Patents

Description

File number: P 17 62 746. 2-31

Applicant: SYNCHRON, druzstvo pro vj ^ oj α kusovou vjrobu mericich pristroju, Praha 3, Borivojova 33

"Procedure for the syntonization of precise oscillators and the arrangement for carrying out this procedure"

The invention relates to a method for the automatic control of precise vibration generators, especially basic oscillators the secondary normal frequency or normal time systems by means of normal frequency signals, which either through a number of radio transmitters be sent to the world in the range of long waves or long waves or are supplied by other means. the The invention further relates to the associated arrangement.

For setting precise frequency-stable basic oscillators whose Frequency for controlling secondary frequency or time standards and the like. Serves, control systems are used, which on the oscillator act in such a way that it is in a consistently coherent phase with the Frequency of the control frequency normal oscillates, of course

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within the limits of technically achievable accuracy under influence of measurement errors, transmission strengths of the control signal, aging the arrangement, especially the quartz and other external influences, such as temperature fluctuations, voltage fluctuations and similar. These devices continuously and steadily operate the tuning organs of the regulated basic oscillator as a function of the respective size of its phase deviations from the ideal state, so that every change in the parameters of the transfer path the normal control signal (e.g. fading, etc.), the properties of the receiver and other parts of the control system, which appear as a change in the phase system of the normal control signal in the comparison point with the signal of the controlled oscillator results in undesired control processes. · The frequency of the controlled oscillator is thereby burdened with the remaining daily variations · The transmission of normal frequency control signals in the range of long and long waves is known to be reliable only during the day when the phase shift at the receiving point compared to the transmitting point is relatively stable. In contrast, significant changes in this shift occur at sunrise and sunset (also by several periods) and during the night still random fluctuations tevf, which then lead to undesired control processes to lead. If the normal control signal fails, the entire control process continues lost. Systems that are intended to prevent this fall are sint very complicated, expensive and prone to failure. In order to achieve large time constants of the controller, it is necessary * the electromechanical The principle to be used in the controller, which is very demanding because of the requirement for continuous operation at low power.

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009834 / 065S

The invention is based on the object of eliminating the aforementioned disadvantages of known control methods for oscillators but above all a substantial limitation of the possibility of the occurrence of an irreversible phase shift of the size of a In multiples of the 2 Tf ", the large frequency fluctuations of the regulated Oscillator in the continuous control process, the dependence of the activity of the control process on random changes and Disturbances in the transmission of the normal frequency control signal reach·

Furthermore, the invention enables a significant simplification of the construction of the devices, which is beneficial in terms of the necessary effort and the susceptibility of the equipment to failure. The invention increases the reliability of the control a very great value. It also enables precise oscillators to be regulated whose frequency differs from the normal control frequency is different, not even in a harmonious relationship with it.

The object of the invention is a method for the automatic control of oscillators, in particular for secondary standard frequency or standard time systems, in which the measured time shift (T *) of the regulated oscillator compared to the normal frequency control signal is converted into a quantity, the value of which can be stored in a memory, and determined in advance, regularly with a constant time interval (T) repeating Determination times (t.) A frequency correction (F,)

using a stored value Cl · ι) the time delay

009834/0655

Shift in the previous determination moment (t..) And the value CC .) Determined in the just present determination moment (t.) Of the time shift is calculated and after this calculation has been carried out, the last determined value (L.) Is stored in the memory and a change

the frequency (f.) of the controlled oscillator by a calculated h

Correction (F,) is carried out, the corrector (F,) after the equation

^F ko J_ (2 T. Fi,) takes place,

_f β 1 1-1

h · T

where f is the nominal frequency of the controlled oscillator. Further

According to the invention, the time shift can be determined as the average value of the time shift in the vicinity of the determination instant will. The arrangement for performing the method according to the invention consists of a time comparator, at the output of which a Computing device with simple memory is connected, which is connected to a program control unit and according to the earlier mentioned algorithm works periodically in investigation moments, which are determined by control pulses at the input of the program control unit, and from one to the computer with memory coupled actuation unit, which adjusts the regulated oscillator

An exact comparison of distant normals of the Due to the properties of the common transmission channels, frequency or time is only in sufficiently long time intervals (T) possible. In these time intervals (1 day and more) the mean

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BATH ORIGINAL

Deviation Δ f in the frequency of the controlled oscillator detected. This is possible in a simple way if the frequency of the control standard corresponds to the frequency of the regulated oscillator (^ ₁ = f «)» Are these frequencies different

(f. £ fn) r can both or just one of them to a different one

located frequency f _{o can be} transposed or converted. at

With very precise oscillators, the frequency deviation is carried out by measuring the phase deviation Δγ at the beginning and at the end of the determination time interval T. The phase shift Δ ^ P of a signal can advantageously be given by a time variable (time shift leading, lagging) Z (t) = <f (t) , respectively. Γ (t) = ^ (t) + k,

2T f 2Jf

can be printed out, the size of the constant k being insignificant for the evaluation of the phase or frequency deviations of the compared standards. This terminology is appropriate because frequency and time are physically reciprocal quantities and the unit of time is defined in terms of the number of periods of an accurately known frequency, and it is also very advantageous in that it enables signals of entirely different frequencies to be compared easily and simply. For a given frequency, there is in principle no difference between the phase deviation Δ Cf and the time shift ^ C (t) under the condition that when determining the phase deviation g Δ ^ f there is an uninterrupted integration of the partial deviations even when the values Φ = 2 IT » 4 ~ j {~. ,, »* U3w.

takes place, Ee means that the values AC ^ = <Κ ··· 4 ^ - ■ * If "

+ CTv etc. can be distinguished. For reasons of general validity, the term time shift Έ (t) is used exclusively, without considering whether it is about the; Comparison of frequency standards or time standards flares.

00SS34 / 0S55

The essence of the invention will become more apparent from the detailed description the control process and the mode of operation of the arrangement explained with reference to the drawing. Show it:

Figure 1 is a block diagram of the inventive control device and

FIG. 2 shows an idealized time diagram of the course of the time shift in two detection intervals and the associated frequency curve of the controlled oscillator.

In the block diagram according to FIG. 1, 1 is a regulated oscillator

denotes that a signal with frequency f, at its output 10

and supplies it to the input 31 of the time comparator device 3 by means of the connecting line 13-31. The second input 32 of the Time comparator device 3 is connected to the output 23 of the source 2 of the standard calibration frequency f. This source 2 is in our Example of a radio receiver for long or long waves · It is However, it goes without saying that the method described is not only used for the regulation of secondary frequency or frequency Time normals are determined and usable by long or long wave transmission. This procedure can be used in all cases where it is necessary to switch off a periodic dependence of the phase of the control signal on the time of day (e.g. with a Transmission of the control signal Via a telephone line, its parameters are variable during the day and night), or where there is an uninterrupted transmission of the control signal during the not possible for a whole day for economic or technical reasons is (e.g., the audio frequency 1 kHz can be used, which

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BATH

by some broadcasters daily regularly for a few hours is sent). As a source 2 of the calibration frequency f can

Also serve an equivalent oscillator in case of conservation of both oscillators acts in a constant frequency ratio. The mechanical or electrical output variable at output 34 is the Input of a simple computer 4 supplied with memory. The output 54 of the function control unit 5 is connected to the second input 45 of this computer 4, and the starting pulse is fed to its input 50 will. The output 46 of the computer 4 is connected to the input 64 of the servo device 6, which by means of the coupling 61-16 with the controlled oscillator 1 is connected so that it causes the tuning of its frequency f.

The individual elements of the arrangement have the following properties: The oscillator tuned to the required precise frequency f is a very stable frequency oscillator that is controlled by a crystal, possibly by quantum processes.

The output 10 of the oscillator can be used to control clocks, frequency synthesizers, used by electronic meters and the like. The time comparator device 3 is generally a device known per se, the output 34 of which is one of the time shift L / (t) of the signal JF of the controlled oscillator 1

from the control signal f of the standard frequency source 2 supplies a proportional size. This time comparator device 3 can be implemented in various known ways. But it can also consist of amplifiers of the control signal, of circuits for a transformation (synthesis) and combination of the frequencies of the regulated oscillator ^ and the control signal, of a phase discriminator ιφο a servomechanically controlled phase shifter, the & sn VjIJU 3-

009834/0655

" ^h " BAD ORIGINAL

continuously follows all changes in the time shift (phase shift) in the necessary range, e.g. - 50 fjs _{t, through its rotation.} The time comparator device 3 can also be implemented without electromechanical ^ circles, e.g. B. by using the elements of analog or digital technology,

The indication of the time shift ^ (t), which can be used as mechanical or electrical quantity can be determined, must be able to be recorded in the memory of the computer 4. The calculator 4 is a simple one Single-purpose computer using a simple algorithm mentioned later is working. It must be able to store the value of the time shift f ·. . in the previous time t. . for the Establish up to the present time t. to keep and

after the calculation of the correction of the frequency F, from the value \ f . . and the C · the time shift at time t.

this last value T ~. to keep in memory. The export this operation is controlled by the program control unit 5. This pulse can be triggered at will, e.g. B. by hand, on best, however, automatically by any clock that is advantageously controlled by the oscillator 1. At the output 46 of the counter If there is a correction signal, the control unit corrects the tuning of the oscillator 1 by the value F, undertakes

Figure 2 is used to derive the algorithm of the computer · 4 with memory. Here, A shows the course of the time shift \ j (t) of the controlled oscillator in relation to the normal control signal as a function of time · It is assumed that

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BATH

the determination points follow one another at regular time intervals of length T,) The time T can be chosen arbitrarily · For very precise oscillators, for example, “the time span of a day _y di T = 24 hours, is suitable Reception of the normal control signal is fully assured and the correction must be made there. If a graphic recording of the time shift ^ f (t) is carried out at the same time, it can be seen whether the controlled oscillator has jumped over one or more periods of the normal control frequency f.

It is assumed that at the time of determination t. . the controlled oscillator is out of tune and has a certain time shift (C., / 0). According to FIG. 2, at time t. , the timing shift C · ι = C (t ..), which with a through the device

given accuracy was determined (which is indicated in Figure 2 by the tolerance range Λ O). At this point in time exists the frequency deviation F.. (as indicated in B), the theoretical for the entire time T up to the further determination time t. remains constant (the own instability of the oscillator 1 not taken into account due to the simplification of the declaration). Of the Value C. . is stored in the memory of the computer 4.

At time t. the Ze.ltverchichtung of the oscillator 1 compared to the normal cost signal has the value u. s ^ f (t,) _f the again through the

Time comparator 3 in the range of accuracy ^ u of the derate was determined. The course of the value of the time shift {/ (t) is in reality not linear between these points, as

00 «83 * / OeSS ' ^{! C} " _BA D G-IGlNAL

draws, but generally has random values, included the aging component «For the purpose of explanation, however, it is sufficient to use a theoretically linear course, as shown, to accept. If at time t. no correction carried out

would have been, it is assumed that the course of the change in the time shift t (t) according to the dashed line of the course (continuation of the connecting line of the points (t.., "V *,) and

(t., C. ) would be, and the value of the displacement would be at time t. . the value C. , «2C /.- V / .. reach. However, since the displacement £,. . s 0, a correction F, proportional to the frequency f., must be introduced

the value 2C ₁ - C. , is.
The relationship that applies

i - ι =

^{T f} h

in words that the change in the time shift (t) is in the same proportion to the length of the determination interval T as the shift in the frequency F. in this interval to the nominal frequency value f. It is similar for the interval t. - """* · ₊ ι

^ HI ₁ "^ i u ^F i (2)

^{T f} h

The frequency correction, which must be carried out at time t, so that in the next investigation instant t. . a time shift C ".. arises, must still be (1) and (2)

00983W0665 "» - _{MD 0R | <3WAL}

F, = F. - F.. = f. \ (Γ., -2 Γ. + t.,) k ι il h T ^υ l + l ι ll '

The relative frequency correction is thus

Λ. ι. {γ _M -2 -C _{1 +} ^ ₁

H '

If at time t. . the Vfert L. .. should reach zero, is the necessary frequency correction of the controlled oscillator

^F ko = - 1. (2 X - IT).

_{f T} ι il

According to this relationship, the computer 4 must operate with memory. An implementation of one that works according to this algorithm Computer is possible in various ways and is not the subject of this invention.

In a number of cases it is more beneficial to use the average Value of the time shift X ~ (t) in the vicinity of the determination time-t. instead of determining the current value, which eliminates the effect of random fluctuations will. The above devices used as the time comparator 3 can. Usually equipped with integrating elements is this · Requirement usually met.

The method and the arrangement ensure that the frequency corrections necessary for maintaining the displacement of the Phase of the controlled oscillator in the required or ascertainable limits are necessary, in their absolute size smaller si.nl

009834/0655 _ ₁₂ _

than with other retuning methods with the same limits of the additional Phase deviations These corrections are known and constant during an interval and an oscillator controlled in this way can e.g. Also serve better for precise measurement of frequencies than known types of regulated oscillators.

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Claims (1)

PATENT CLAIMS: le method for the automatic control of oscillators, in particular for secondary normal frequency or normal time systems, characterized in that the measured time shift ((, (t)) of the controlled oscillator compared to the normal frequency control signal is converted into a variable, the value of which is stored in a memory can and in advance determined, regularly with a constant time interval (T) repeating determination times (t.) a frequency correction (F,) using a stored value ( Tj. «) of the time shift ( C) in the previous determination times (t.,) and the value (T \) determined in the present determination time (t.) the time shift is calculated and after this calculation the last determined value (C-.) is stored in the memory and a change in the frequency (f.) of the controlled oscillator a calculated correction (F,) is carried out, where the correction (F,) depending on the equation ^F ko »I (2 1. - T ₄₁ ) takes place, π
where f, is the nominal frequency of the controlled oscillator. 2. The method according to claim 1, characterized in that that the time shift ("£ *) as the average value of the time -H-009834/0656 shift determined in the vicinity of the investigation moment will" 3. Arrangement for performing the method according to claim 1 and / or 2, characterized in that a computing device (4) with a simple memory is connected to the output (34) of a time comparator (3) known per se, which is connected to a program control unit (5 ) is connected, and according to the algorithm mentioned in claim 1 works periodically at determination times (t.) at regular intervals (T) by control pulses at the input (50) of the program control unit (5), and that at the output (46) of the computing device ( 4) an actuating unit (6) is connected to the memory, which readjusts the tuning of the controlled oscillator (1) by a correction (F ₁ ). KO PATENT ADVOCATE 009834 / 06SS