CA1114511A - Data processing apparatus - Google Patents
Data processing apparatusInfo
- Publication number
- CA1114511A CA1114511A CA328,224A CA328224A CA1114511A CA 1114511 A CA1114511 A CA 1114511A CA 328224 A CA328224 A CA 328224A CA 1114511 A CA1114511 A CA 1114511A
- Authority
- CA
- Canada
- Prior art keywords
- signals
- measure
- peak
- correlator
- tracking
- 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
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06G—ANALOGUE COMPUTERS
- G06G7/00—Devices in which the computing operation is performed by varying electric or magnetic quantities
- G06G7/12—Arrangements for performing computing operations, e.g. operational amplifiers
- G06G7/19—Arrangements for performing computing operations, e.g. operational amplifiers for forming integrals of products, e.g. Fourier integrals, Laplace integrals, correlation integrals; for analysis or synthesis of functions using orthogonal functions
- G06G7/1928—Arrangements for performing computing operations, e.g. operational amplifiers for forming integrals of products, e.g. Fourier integrals, Laplace integrals, correlation integrals; for analysis or synthesis of functions using orthogonal functions for forming correlation integrals; for forming convolution integrals
- G06G7/1935—Arrangements for performing computing operations, e.g. operational amplifiers for forming integrals of products, e.g. Fourier integrals, Laplace integrals, correlation integrals; for analysis or synthesis of functions using orthogonal functions for forming correlation integrals; for forming convolution integrals by converting at least one the input signals into a two level signal, e.g. polarity correlators
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/704—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow using marked regions or existing inhomogeneities within the fluid stream, e.g. statistically occurring variations in a fluid parameter
- G01F1/708—Measuring the time taken to traverse a fixed distance
- G01F1/712—Measuring the time taken to traverse a fixed distance using auto-correlation or cross-correlation detection means
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/15—Correlation function computation including computation of convolution operations
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Data Mining & Analysis (AREA)
- Computational Mathematics (AREA)
- Pure & Applied Mathematics (AREA)
- Software Systems (AREA)
- Computing Systems (AREA)
- Computer Hardware Design (AREA)
- Algebra (AREA)
- Fluid Mechanics (AREA)
- Databases & Information Systems (AREA)
- General Engineering & Computer Science (AREA)
- Measuring Volume Flow (AREA)
- Complex Calculations (AREA)
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to apparatus for tracking the peak of a correlation function between two signals.
A first correlator is responsive to the signals and provides a coarse measure of the position of the peak. A second correlator is also responsive to the signals and tracks the position of the peak when the coarse measure corresponds to the tracking range of the second correlator. The first correlator is connected to the second correlator for causing the tracking range thereof to correspond to the coarse measure. The apparatus finds particular use as a flowmeter in which flow velocity is deter-mined by identifying the time delay between the two signals.
If the distance between the points of derivation of the two signals is constant, the flow velocity is inversely proport-ional to the identified time delay.
The present invention relates to apparatus for tracking the peak of a correlation function between two signals.
A first correlator is responsive to the signals and provides a coarse measure of the position of the peak. A second correlator is also responsive to the signals and tracks the position of the peak when the coarse measure corresponds to the tracking range of the second correlator. The first correlator is connected to the second correlator for causing the tracking range thereof to correspond to the coarse measure. The apparatus finds particular use as a flowmeter in which flow velocity is deter-mined by identifying the time delay between the two signals.
If the distance between the points of derivation of the two signals is constant, the flow velocity is inversely proport-ional to the identified time delay.
Description
--~ 1114511 , The present invention relates to data processing apparatus and more particularly to apparatus for tracking the peak of correlation function between two signals.
In many applications, it is necessary to monitor a correlation function between two signals and to determine when the correlation functions reaches a maximum value. One such application arises in connection with a method of measuring flow in which the flow velocity is determined by identifying the time delay between two related signals, one signal being derived downstream of the flow with respect to the other signal. If the distance between the points of derivation of the two signals is constant, the flow velocity will then be inversely proportional to the identified time delay.
Broadly speaking, the present invention provides apparatus for tracking the peak of a correlation function between two signals, the apparatus comprising, in combination, first correlator means responsive to the signals for providing a coarse measure of the position of the peak and second correlator means responsive to the signals for tracking the position when the coarse measure corresponds to the tracking range of the second correlator means; the first correlator means being connected to the second correlator means for causing the tracking range to correspond to the coarse measure.
Features and advantages of the present invention will become apparent from the following description of an embodiment thereof given by way of example with reference to the accompany-ing drawings in which~
Figure la is a schematic diagram showing the relation-,,, ~ sd~
` :;` 1~L14S~l ,~' .. ~ ship between two internal variables of a transport process :
and their external measurable signals; :
Figure lb is a block diagram showing correlation function peak tracking apparatus;
Figure 2 is a graphical representation of a correlation function and its differential with respect to - delay time;
Figure 3 is a block diagram of a word-controlled shift register; and '`
' 10 ., ' ,.', ,' ' :~.
'' ' ~ .
, ~
:
`~
sd/~ -lA-1~i145-11 Figure 4 is a block diagram showing correlation function peak tracking apparatus incorporating coarse-fine resolution.
Referring to Figure la, there is shown in sche-matic form the relationship between internal variables, x' and y' of a transport process T(S), and external measurable signals x and y. Laplace transforms Ll(S) and L2(S) act as -transfer functions between x' and x, and y' and y respectively.
It can be shown that if the auto-correlation function of x is RXx(S) and the cross-correlation function between x and y is Ryx(S), then:_ R x(S) = Ll(S).Ll( S). Rx'x'( ) and Ryy(S) = L2(S).T(S). L2(-S).T(-S).Rx,x,(S) Eliminating Rx'x'(S) gives -Ryy(S) = L2(S)-T(S) L2(~S) T(S) Rxx(S) Ll(S) Ll(-S) Thus the effective transfer function relatlng y to x is L2(S).T(S) ~ .
and therefore RyX(S) = L2(S).T(S) . R (S) .... (1) (S) When both transfer functions Ll and L2 are unity, RyX(S) = T(S).Rxx(S) .... (2) when Ll = 1 and L2 = ST (where T iS the delay time) RyX(S) = Sl[T(S).Rxx(S)] .... ~3) In the time delay domain, this is equivalent to -:
:
~L14511 ~ ~
the differentiation of equation (2) with respect to time delay.
Where it is desired to carry out these functions with electronic circuits, an ideal differentiator of the sort Ll = 1 and L2 = Sl need not be used since Ll = -~
1/(1 + Sl) and L2 = ST/(1 + ST) are easily implemented using resistance-capacitance circuits and still give the ratio S~ -to conform with equation (3) above.
The essential features of delay-lock-loop, cor-relation function peak tracking apparatus are shown in Figure lb. One input signal x(t) is fed through a polarity detector to a shift register SR, which introduces a delay to the signal. This delayed signal is then fed to one input :
of a multiplier. A second input signal y(t) is fed througha differentiating circuit to the second input of the multi-plier. The output of the multiplier is fed through a smooth-ing circuit to an integrator whose output is fed to a voltage controlled oscillator VCO. The voltage controlled oscillator VCO provides the clock frequency setting the shift register delay ~
If the feedback loop comprising the integrator ¦ :
and VCO is broken and the shift register deIay externally ¦
controlled, then it can be shown that the differentiation ¦
of the signal y(t) results in a voltage variation appearing at the output of the smoothing circuit which is representa-tive of the differentiated cross-correlation function Ryx, as the shift register delay is slowly swept through the de-lay range of the function.
The cross-correlation function Ryx and its . :
~ ~ 3 -i 1~14S~l `
. i differential with respect to delay time are shown graphically in Figure 2.
- The differentiated function, illustrated by a broken line, is bipolar and hence the stable operating point of the closed-loop negative feedback system will be obtained when the differentiated function equals zero. This point cor-.
responds to the peak of-the correlation function Ryx, and slow changes of the peak position will be tracked by this apparatus.
Previously proposed differentiation methods have used the difference between two correlation functions, one delayed with respect to the other. The difference signal is proportional to the differentiated correlation function. ~low-ever, since the zero-crosslng point of the differentiated function is obtained from the subtraction of parts of the cor-relation functions substantially less than peak value, the accuracy of the result obtained will be reduced due to noise arising from increased variance as the function magnitude de-creases.
Where more rapid changes of peak position are to be tracked, it is an advantage to initially obtain a coarse ~ , , , indication of the peak position. This obviates the need to use the apparatus of Figure 1 in a search mode of operation which would cause a long time-delay in the system response to large changes of peak position. The use of a coarse peak in-dicator also removes the possibility that spurious, smaller magnitude peaks will be locked on to before the main peak has been found.
X
- :
1~14S:~l ~, The preferred embodiment of the present inven- -tion therefore provides a coarse-fine system approach. A
digital correlator with a relatively small number of delay increments will provide a coarse indication of the peak position. This may be used to constrain the peak tracking --range of a delay-locked loop to the immediate vicinity of the most significant peak thereby removing the need for-a search mode of operation. By using this technique it will be possible to construct correlation function peak tracking apparatus, e.g. for use in a correlation flowmeter, having a virtually , continuous output resolution.
Figure 3 shows a word~controlled shift register.
A binary word Np, in this case proportional to the position of the most significant peak of the function,-controls logic 1 ;
switches SW connecting the various stages SRS of the shift ¦: `
register. When a binary bit of the word is one, a shift register proportional in length to the binary weighting of the bit is connected into the series chain of shift registers wherea~ when the bit is zero the stage is by-passed by a short-circuit. A digital correlator quantising the time delay range into a relatively small number of increments produces the binary word Np proportional to the approximate position of the most significant peak.
Figure 4 shows a block diagram of a complete con-strained peak tracking system. The coarse measure of the position of the peak (Np) sets the length of a variable delay shift register (SR). The clock frequency Fc of this register i6 supplied by a voltage coDtrolled osclllator ~vco) forming .~ .
:: :: : . , , : .: .. .
S~l part of the delay-lock loop in a similar fashio to that of ~ -Figure 1. The integral V2 of the smoothed signal Vl, controls the VCO and hence the clock frequency Fc. The integrator out- ;~
put V2 effectively adjusts Fc until Vl is nulled as described above and then the time delay position of the peak of the function will be given by -Time delay = Np F
.
For correlation flowmeter applications an output inversely proportional to time delay is required i.e. -Flow ~ c N
- ,' ',~, - This function is implemented by using a variable modulus counter circuit controlled by the coarse peak indica-~`, tion Np with the clock frequency to voltage converter FVC which produces a voltage VO proportional to flow. The voltage VO can ,, activate conventional indicating means such as a panel meter, 11 pen recorder or digital read out.
An alternative output circuit may be formed as 1-follows. The output from the voltage controlled oscillator is given by ~i ., .
F K V
' :, ' where V2 = ~ Vldt where Vl = Kl ~ ~
`.`
'. ~
~n 6 --- . . . - - ~ -. . . ~ . i 1~14S~
However the equ-tion for Fc can be rewritten to give V2 = c _ K3 ' Hence it is possible to form a voltage Vc given by .'' , ~
s and therefore a multiplying DAC circuit may be connected to - ~ , : . . -the output of the integrator to form a voltage proportional to flow rate.
~: ' , , ~`'~
., ~
.
., ' '' ,'~.
, ' .. '~
.
:
~'
In many applications, it is necessary to monitor a correlation function between two signals and to determine when the correlation functions reaches a maximum value. One such application arises in connection with a method of measuring flow in which the flow velocity is determined by identifying the time delay between two related signals, one signal being derived downstream of the flow with respect to the other signal. If the distance between the points of derivation of the two signals is constant, the flow velocity will then be inversely proportional to the identified time delay.
Broadly speaking, the present invention provides apparatus for tracking the peak of a correlation function between two signals, the apparatus comprising, in combination, first correlator means responsive to the signals for providing a coarse measure of the position of the peak and second correlator means responsive to the signals for tracking the position when the coarse measure corresponds to the tracking range of the second correlator means; the first correlator means being connected to the second correlator means for causing the tracking range to correspond to the coarse measure.
Features and advantages of the present invention will become apparent from the following description of an embodiment thereof given by way of example with reference to the accompany-ing drawings in which~
Figure la is a schematic diagram showing the relation-,,, ~ sd~
` :;` 1~L14S~l ,~' .. ~ ship between two internal variables of a transport process :
and their external measurable signals; :
Figure lb is a block diagram showing correlation function peak tracking apparatus;
Figure 2 is a graphical representation of a correlation function and its differential with respect to - delay time;
Figure 3 is a block diagram of a word-controlled shift register; and '`
' 10 ., ' ,.', ,' ' :~.
'' ' ~ .
, ~
:
`~
sd/~ -lA-1~i145-11 Figure 4 is a block diagram showing correlation function peak tracking apparatus incorporating coarse-fine resolution.
Referring to Figure la, there is shown in sche-matic form the relationship between internal variables, x' and y' of a transport process T(S), and external measurable signals x and y. Laplace transforms Ll(S) and L2(S) act as -transfer functions between x' and x, and y' and y respectively.
It can be shown that if the auto-correlation function of x is RXx(S) and the cross-correlation function between x and y is Ryx(S), then:_ R x(S) = Ll(S).Ll( S). Rx'x'( ) and Ryy(S) = L2(S).T(S). L2(-S).T(-S).Rx,x,(S) Eliminating Rx'x'(S) gives -Ryy(S) = L2(S)-T(S) L2(~S) T(S) Rxx(S) Ll(S) Ll(-S) Thus the effective transfer function relatlng y to x is L2(S).T(S) ~ .
and therefore RyX(S) = L2(S).T(S) . R (S) .... (1) (S) When both transfer functions Ll and L2 are unity, RyX(S) = T(S).Rxx(S) .... (2) when Ll = 1 and L2 = ST (where T iS the delay time) RyX(S) = Sl[T(S).Rxx(S)] .... ~3) In the time delay domain, this is equivalent to -:
:
~L14511 ~ ~
the differentiation of equation (2) with respect to time delay.
Where it is desired to carry out these functions with electronic circuits, an ideal differentiator of the sort Ll = 1 and L2 = Sl need not be used since Ll = -~
1/(1 + Sl) and L2 = ST/(1 + ST) are easily implemented using resistance-capacitance circuits and still give the ratio S~ -to conform with equation (3) above.
The essential features of delay-lock-loop, cor-relation function peak tracking apparatus are shown in Figure lb. One input signal x(t) is fed through a polarity detector to a shift register SR, which introduces a delay to the signal. This delayed signal is then fed to one input :
of a multiplier. A second input signal y(t) is fed througha differentiating circuit to the second input of the multi-plier. The output of the multiplier is fed through a smooth-ing circuit to an integrator whose output is fed to a voltage controlled oscillator VCO. The voltage controlled oscillator VCO provides the clock frequency setting the shift register delay ~
If the feedback loop comprising the integrator ¦ :
and VCO is broken and the shift register deIay externally ¦
controlled, then it can be shown that the differentiation ¦
of the signal y(t) results in a voltage variation appearing at the output of the smoothing circuit which is representa-tive of the differentiated cross-correlation function Ryx, as the shift register delay is slowly swept through the de-lay range of the function.
The cross-correlation function Ryx and its . :
~ ~ 3 -i 1~14S~l `
. i differential with respect to delay time are shown graphically in Figure 2.
- The differentiated function, illustrated by a broken line, is bipolar and hence the stable operating point of the closed-loop negative feedback system will be obtained when the differentiated function equals zero. This point cor-.
responds to the peak of-the correlation function Ryx, and slow changes of the peak position will be tracked by this apparatus.
Previously proposed differentiation methods have used the difference between two correlation functions, one delayed with respect to the other. The difference signal is proportional to the differentiated correlation function. ~low-ever, since the zero-crosslng point of the differentiated function is obtained from the subtraction of parts of the cor-relation functions substantially less than peak value, the accuracy of the result obtained will be reduced due to noise arising from increased variance as the function magnitude de-creases.
Where more rapid changes of peak position are to be tracked, it is an advantage to initially obtain a coarse ~ , , , indication of the peak position. This obviates the need to use the apparatus of Figure 1 in a search mode of operation which would cause a long time-delay in the system response to large changes of peak position. The use of a coarse peak in-dicator also removes the possibility that spurious, smaller magnitude peaks will be locked on to before the main peak has been found.
X
- :
1~14S:~l ~, The preferred embodiment of the present inven- -tion therefore provides a coarse-fine system approach. A
digital correlator with a relatively small number of delay increments will provide a coarse indication of the peak position. This may be used to constrain the peak tracking --range of a delay-locked loop to the immediate vicinity of the most significant peak thereby removing the need for-a search mode of operation. By using this technique it will be possible to construct correlation function peak tracking apparatus, e.g. for use in a correlation flowmeter, having a virtually , continuous output resolution.
Figure 3 shows a word~controlled shift register.
A binary word Np, in this case proportional to the position of the most significant peak of the function,-controls logic 1 ;
switches SW connecting the various stages SRS of the shift ¦: `
register. When a binary bit of the word is one, a shift register proportional in length to the binary weighting of the bit is connected into the series chain of shift registers wherea~ when the bit is zero the stage is by-passed by a short-circuit. A digital correlator quantising the time delay range into a relatively small number of increments produces the binary word Np proportional to the approximate position of the most significant peak.
Figure 4 shows a block diagram of a complete con-strained peak tracking system. The coarse measure of the position of the peak (Np) sets the length of a variable delay shift register (SR). The clock frequency Fc of this register i6 supplied by a voltage coDtrolled osclllator ~vco) forming .~ .
:: :: : . , , : .: .. .
S~l part of the delay-lock loop in a similar fashio to that of ~ -Figure 1. The integral V2 of the smoothed signal Vl, controls the VCO and hence the clock frequency Fc. The integrator out- ;~
put V2 effectively adjusts Fc until Vl is nulled as described above and then the time delay position of the peak of the function will be given by -Time delay = Np F
.
For correlation flowmeter applications an output inversely proportional to time delay is required i.e. -Flow ~ c N
- ,' ',~, - This function is implemented by using a variable modulus counter circuit controlled by the coarse peak indica-~`, tion Np with the clock frequency to voltage converter FVC which produces a voltage VO proportional to flow. The voltage VO can ,, activate conventional indicating means such as a panel meter, 11 pen recorder or digital read out.
An alternative output circuit may be formed as 1-follows. The output from the voltage controlled oscillator is given by ~i ., .
F K V
' :, ' where V2 = ~ Vldt where Vl = Kl ~ ~
`.`
'. ~
~n 6 --- . . . - - ~ -. . . ~ . i 1~14S~
However the equ-tion for Fc can be rewritten to give V2 = c _ K3 ' Hence it is possible to form a voltage Vc given by .'' , ~
s and therefore a multiplying DAC circuit may be connected to - ~ , : . . -the output of the integrator to form a voltage proportional to flow rate.
~: ' , , ~`'~
., ~
.
., ' '' ,'~.
, ' .. '~
.
:
~'
Claims (4)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for tracking the peak of a correlation function between two signals, said apparatus comprising, in combination, first correlator means responsive to said signals for providing a coarse measure of the position of said peak and second correlator means responsive to said signals for tracking said position when said coarse measure corresponds to the tracking range of said second correlator means; said first correlator means being connected to said second correlator means for causing said tracking range to correspond to said coarse measure.
2. The apparatus of Claim 1, wherein said second correlator means has means for providing delay which determines said track-ing range and is variable by said coarse measure such as to cause said tracking range to correspond to said coarse measure.
3. The apparatus of Claim 2, wherein the last said means includes delay-lock-loop means for providing both said delay and a fine measure of the position of said peak within said tracking range.
4. A flowmeter including the apparatus of Claim 3, wherein said second correlator means includes oscillator means producing a control signal having a frequency corresponding to said fine measure,and there being variable modulus counter means having its modulus controlled by said coarse measure and having said control signal for an input whereby to produce a count output inversely proportioned to said fine measure; said flowmeter including a pair of detectors located adjacent a flowing fluid for producing said two signals such that one of said signals identifies given elements of said fluid at a first given location and the other of said signals identifies the same given elements of said fluid but at a second given location, each said location being spaced, one from the other, along the path of flow of said fluid, whereby said count output is a measure of the rate of flow of said fluid from one said location to the other.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2280078 | 1978-05-25 | ||
| GB22800/78 | 1978-05-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1114511A true CA1114511A (en) | 1981-12-15 |
Family
ID=10185261
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA328,224A Expired CA1114511A (en) | 1978-05-25 | 1979-05-24 | Data processing apparatus |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0019618A1 (en) |
| JP (1) | JPS55500512A (en) |
| CA (1) | CA1114511A (en) |
| DE (1) | DE2952812A1 (en) |
| FR (1) | FR2476351A1 (en) |
| GB (1) | GB2039110B (en) |
| IT (1) | IT7922990A0 (en) |
| WO (1) | WO1979001119A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61207973A (en) * | 1985-03-13 | 1986-09-16 | Mitsubishi Electric Corp | Correlation type time difference meter |
| US4729109A (en) * | 1985-05-29 | 1988-03-01 | University Of Illinois | Method and apparatus for measuring the displacements of particle images for multiple exposure velocimetry |
| DE3633769A1 (en) * | 1986-10-03 | 1988-04-14 | Endress Hauser Gmbh Co | DIGITAL CORRELATOR |
| FI87493C (en) * | 1991-12-23 | 1993-01-11 | Kytoelae Instrumenttitehdas | OVER ANCHORING FOR OVER MAINTENANCE AV STROEMNINGSHASTIGHETEN AV GASER OCH / ELLER STORHETER SOM KAN HAERLEDAS FRAON DENNA |
| GB2327761A (en) * | 1997-07-28 | 1999-02-03 | Pcme Limited | Velocity measurement |
| CA2557380C (en) * | 2005-08-27 | 2012-09-25 | Schlumberger Canada Limited | Time-of-flight stochastic correlation measurements |
| US9222817B2 (en) * | 2013-03-15 | 2015-12-29 | Amphenol Thermometrics, Inc. | Systems and methods for hybrid flow sensing |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3982114A (en) * | 1961-08-28 | 1976-09-21 | Trw Inc. | Signal processing system |
| FR2041579A5 (en) * | 1969-04-30 | 1971-01-29 | Thomson Csf | |
| US3660647A (en) * | 1969-12-24 | 1972-05-02 | Us Navy | Automatic signal delay tracking system |
| GB1398381A (en) * | 1971-06-10 | 1975-06-18 | Kent Instruments Ltd | Correlators |
| DE2133942C3 (en) * | 1971-07-02 | 1973-11-29 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Arrangement for the non-contact measurement of the speed of an object |
| DE2705159A1 (en) * | 1977-02-04 | 1978-08-17 | Licentia Gmbh | Finding correlation function maximum - is by auto-correlator balancing determination of band central frequency using delay circuits |
-
1979
- 1979-05-24 JP JP50079179A patent/JPS55500512A/ja active Pending
- 1979-05-24 WO PCT/GB1979/000076 patent/WO1979001119A1/en unknown
- 1979-05-24 CA CA328,224A patent/CA1114511A/en not_active Expired
- 1979-05-24 GB GB8002114A patent/GB2039110B/en not_active Expired
- 1979-05-24 DE DE792952812A patent/DE2952812A1/en active Pending
- 1979-05-25 IT IT7922990A patent/IT7922990A0/en unknown
-
1980
- 1980-01-03 EP EP79900522A patent/EP0019618A1/en not_active Withdrawn
- 1980-12-05 FR FR8026167A patent/FR2476351A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| EP0019618A1 (en) | 1980-12-10 |
| FR2476351A1 (en) | 1981-08-21 |
| DE2952812A1 (en) | 1980-12-11 |
| JPS55500512A (en) | 1980-08-14 |
| GB2039110A (en) | 1980-07-30 |
| IT7922990A0 (en) | 1979-05-25 |
| WO1979001119A1 (en) | 1979-12-27 |
| GB2039110B (en) | 1982-11-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |