EP0473731A1 - Procede et dispositif de comparaison de deux signaux analogiques variables. - Google Patents
Procede et dispositif de comparaison de deux signaux analogiques variables.Info
- Publication number
- EP0473731A1 EP0473731A1 EP91900037A EP91900037A EP0473731A1 EP 0473731 A1 EP0473731 A1 EP 0473731A1 EP 91900037 A EP91900037 A EP 91900037A EP 91900037 A EP91900037 A EP 91900037A EP 0473731 A1 EP0473731 A1 EP 0473731A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- signals
- circuit
- analog signals
- signal
- correlation
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 19
- 230000001131 transforming effect Effects 0.000 claims abstract description 10
- 238000009499 grossing Methods 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 4
- 230000005236 sound signal Effects 0.000 claims description 2
- 230000000737 periodic effect Effects 0.000 claims 1
- 230000001419 dependent effect Effects 0.000 abstract description 2
- 230000006870 function Effects 0.000 description 9
- 230000010363 phase shift Effects 0.000 description 9
- 238000004364 calculation method Methods 0.000 description 8
- 238000005314 correlation function Methods 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/005—Circuits for comparing several input signals and for indicating the result of this comparison, e.g. equal, different, greater, smaller (comparing phase or frequency of 2 mutually independent oscillations in demodulators)
Definitions
- the invention relates to a method and a device for comparing two variable analog signals, for example over time, such as audio or video signals, which are either different from each other, or identical but offset in time.
- Various devices are also known for measuring the phase shift between two analog sinusoidal signals of the same frequency.
- these devices are not applicable to signals which are not purely sinusoidal, such as audio or video signals received or produced by radio or television receivers.
- the object of the invention is in particular to simplify the abovementioned methods and systems of digital calculation and therefore to greatly reduce their cost while retaining the desired speed and accuracy of establishing the correlation. It also aims to measure the correlation between two analog signals of the aforementioned type. which does not use a time or phase measurement.
- the invention proposes for this purpose, a comparison method of two variable analogue signals of establishing a correlation signal between the analog signals and to check based on the values of this .signal if 'are identical or not between analog signals, characterized in that, the signals to be compared being either identical but offset in time, or different, and covering a predetermined frequency band, it consists:
- this method also consists in transforming each analog signal into a binary logic signal by detecting zero crossings of this analog signal, and assigning a first logic value to the signal when it is positive, and a second logical value when it is negative.
- Detecting the zero crossing of the analog signals allows to obtain in a simple way a dynamic excel ⁇ slow (of the order of 60 to 80dB) which cor ⁇ respondrait at least 12 bit resolution in the -. - known processes of numerical calculation.
- the method also consists in connecting the output of the circuit . logic to a low-pass filter to realize the aforementioned sum function.
- the invention also provides a device for comparing two variable analog signals, comprising means for establishing a correlation signal between these two analog signals and means for comparing this signal with a predetermined value to verify whether or not there is identity between the analog signals, characterized in that, these analog signals being either identical and offset in time, or different, and covering a predetermined frequency band, this device comprises two channels analog signal processing parallels, one of which includes means for shifting one of the signals in time with respect to the other, the offset being equal to 1/4 of the period at the center frequency of the frequency band above, these two channels each comprising in series circuits for transforming analog signals into binary logic signals, a logic circuit of the multiplier or OR type exclusive, a circuit for establishing by summing a correlation signal S1, S2, and a circuit for adding the absolute values of the two correlation signals S1, S2, producing an output one.
- correlation signal S substantially independent of a shift in the time between the aforementioned analog signals.
- a low-pass filter at the output of each logic circuit makes it possible to obtain the value of the correlation signal
- the output of the addition circuit is connected to the input of a low-pass filter, performing a smoothing of the correlation signal.
- the device according to the invention also comprises, at the input, circuits for upgrading analog signals, such as, for example, circuits with automatic gain control, and bandpass filters.
- circuits for upgrading analog signals such as, for example, circuits with automatic gain control, and bandpass filters.
- the circuits for transforming analog signals into binary logic signals are advantageously signal comparison circuits. analogical to a determined value, in particular the zero value, allowing the detection of the passage of the analog signals by zero and the attribution to these signals of two binary values according to whether they are positive or negative.
- the cost of a 'se ⁇ lon device of the invention is much lower than conventional tive disposi ⁇ numerical calculation of a correlation function, and its performance is excellent.
- FIG. 2 schematically shows the essential circuits of the device according to the invention
- FIG. 3 schematically shows the essential circuits of the device according to the invention
- FIG. 3 schematically shows the essential circuits of the device according to the invention
- FIG. 3 schematically shows the essential circuits of the device according to the invention
- FIG. 3 schematically shows the essential circuits of the device according to the invention
- FIG. 3 schematically shows the essential circuits of the device according to the invention
- FIG. 1 represents an example of application of the method and of the device according to the invention.
- the reference 10 designates a radio or television receiver, connected to an antenna 12 and associated with an apparatus 14 for detecting the frequency to which the receiver 10 is tuned.
- This device 14 comprises a reference receiver 16, also connected to the antenna 12, a correlation device 18 according to the invention, a microprocessor 20 for processing information, a memory 22 for recording data , an electronic interface circuit 24 for controlling the receiver 16 under the control of the microprocessor 20, and a data clock 25.
- receivers 10 and 16 are linked to the inputs of the correlation device 18, the output of which is connected to an input of the microprocessor 20.
- the latter by means of the interface 24, performs a systematic scanning of the ' - frequencies received by receiver 16 from reference, the output signals of which are compared with those of the receiver 10 by the device 18.
- the correlation between these signals establishes that the receivers 10 and 16 are set to the same frequency.
- the correlation dates and the corresponding frequencies are recorded in the memory 22 from which they can then be extracted and used.
- FIG. 2 schematically represents the constitution of a correlation device 18 according to
- the audio or video signals produced by the receivers 10 and 16 are applied to input circuits notably comprising leveling circuits 26, such as self-monitoring circuits.
- the bandwidth of the filters 28 is by
- each filter 28 is applied to the input of a circuit 30 for transforming the analog signal.
- the circuits 30 can therefore be simple comparators, the positive inputs of which receive the output signals from the filters 28 and the negative inputs of which
- the outputs of the two comparators 30 are linked to the two inputs of a logic circuit 32 of the exclusive OR type, the output signal of which is a binary logic signal, of high level (for example 1) when the two
- circuit 32 35 input signals are identical, and of low level (0 or -1), when the two input signals are different.
- the function of circuit 32 is therefore equivalent to logical multiplication.
- circuit 32 The output of circuit 32 is connected to a low-pass filter 34 which adds the output signals of logic circuit 32, and which produces a correlation signal between the signals to be compared.
- the variation in the ratio S1 / S0 has been shown in FIG. 3 as a function of a phase shift between the signals to be compared. ' - We see that this ratio is equal to 1 when the phase shift is zero or multiple of 2 ⁇ , that it is equal to 0 for phase shifts of 90 degrees, 270 degrees etc ... and that it is equal to -1 for phase shifts of ⁇ , 3 ⁇ , etc. (the variation of this ratio between the values 1 and -1 supposes that the binary values of the output signal of the logic circuit 32 are 1 and -1).
- the graph in FIG. 3 shows that there is in fact a total loss of correlation at the output of circuit 34 when the phase shift between the signals to be compared is close to ⁇ / 2, 3 ⁇ / 2, etc.
- the invention provides (FIG. 2) that the outputs of circuits 28 are connected to the inputs of circuit 36 adding an offset of a quarter of period T / 4 to the central frequency of the bandwidth of filters 28 to 1. one of the analog signals, with respect to the other analog signal.
- the outputs of circuit 36 are connected to the positive inputs of comparators 30 whose outputs are connected to the inputs of a logic circuit -32. identical to circuit 32 previously described.
- the output of this logic circuit is connected to the input of a low-pass filter 34 whose output signal S2 is comparable to the aforementioned output signal SI, but is offset with respect thereto.
- the graph in FIG. 4 represents the variation of the S2 / S0 ratio as a function of a phase shift between the signals to be compared.
- the outputs of the filters 34 are therefore connected to the inputs of circuits 38 for absolute enhancement (for example full-wave rectification circuits) whose outputs are connected to the inputs of an adder circuit 40.
- the output signal S of circuit 40 is a correlation signal which is appreciably independent of the offset between the signals to be compared, and the variation of the ratio of which to the correlation signal S0 is shown in FIG. 5.
- This signal S can be applied to the input of a smoothing circuit 42 such as a low-pass filter, the output of which is connected to the positive input of a comparator 44.
- the negative input of this comparator receives a ten ⁇ sion of predetermined value to which the output signal of circuit 42 is compared.
- the output signal of comparator 44 is applicable to an input of the microprocessor stopper 20 of the apparatus 14 of FIG. 1.
- the audio or video signals produced by the receivers 10 and 16 are applied to the leveling circuits 26, then processed by the bandpass filters 28 and transformed into binary logic signals by the comparators 30. They are then compared between them by the logic circuit 32, a first time directly, a second time after one of these signals has undergone a shift of a quarter of a period at the central frequency of the passband of the filters 28, correlation signals are established by the low-pass filters 34, and the absolute values of these signals are added to obtain a correlation signal little dependent on the shift between the initial analog signals. This correlation signal is smoothed and compared to a predetermined value. If it is greater than this value, the analog signals will be considered to be identical, while they will be considered to be different from each other if the correlation signal is less than the predetermined value.
- the correlation device is therefore relatively simple and has the significant advantage of working on a single bit, unlike comparable digital calculation systems used in the prior art , which generally operate on 8 or 16 bit digital resolution.
- a variant embodiment of the device is shown diagrammatically in FIG. 6.
- the output of each exclusive OR circuit 32 controls a counter-down-counter circuit .46, which counts by increase when the output signal from circuit 32 is at level +1, and by decrease when this output signal is at level -1.
- a timer circuit 48 associated with a clock 50 periodically resets the circuits 46 to zero.
- the sum of the absolute values of the contents of the two circuits 46 is calculated by an adder circuit 52 and compared by a circuit 54 to a double threshold (symmetrical thresholds relative to zero).
- the output of comparator 54 provides a correlation or non-correlation decision signal between the initial analog signals.
- the adder circuit 52 performs either the sum of the signals S1 and S2 of the circuits 46 when they are of the same sign, or their subtraction when they are of opposite sign. It is controlled for this by the sign bits' si and s2 of the signals S1 and S2.
- the invention is of course applicable to analog signals other than audio and video signals, and it also applies to analog signals which vary as a function of another parameter than time.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar Systems Or Details Thereof (AREA)
- Television Receiver Circuits (AREA)
- Circuits Of Receivers In General (AREA)
- Complex Calculations (AREA)
- Signal Processing Not Specific To The Method Of Recording And Reproducing (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT91900037T ATE103077T1 (de) | 1989-12-01 | 1991-06-28 | Verfahren und anordnung zum vergleich zweier veraenderlicher analogsignale. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8915906 | 1989-12-01 | ||
FR8915906A FR2655439B1 (fr) | 1989-12-01 | 1989-12-01 | Procede et dispositif de comparaison de deux signaux analogiques variables. |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0473731A1 true EP0473731A1 (fr) | 1992-03-11 |
EP0473731B1 EP0473731B1 (fr) | 1994-03-16 |
Family
ID=9388062
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP91900037A Expired - Lifetime EP0473731B1 (fr) | 1989-12-01 | 1991-06-28 | Procede et dispositif de comparaison de deux signaux analogiques variables |
Country Status (7)
Country | Link |
---|---|
US (1) | US5305243A (fr) |
EP (1) | EP0473731B1 (fr) |
JP (1) | JPH04505366A (fr) |
CA (1) | CA2046652A1 (fr) |
DE (1) | DE69007477D1 (fr) |
FR (1) | FR2655439B1 (fr) |
WO (1) | WO1991008493A2 (fr) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3102734B2 (ja) * | 1993-09-29 | 2000-10-23 | 株式会社ケンウッド | 相関検出器 |
DE19749803A1 (de) * | 1997-11-11 | 1999-05-27 | Sensopart Industriesensorik Gm | Vorrichtung zur Ermittlung der Beleuchtungsposition mit einer positionsempfindlichen photoelektrischen Detektoreinrichtung |
ATE319163T1 (de) * | 1998-11-17 | 2006-03-15 | Koninkl Philips Electronics Nv | Extrahieren von zusatzdaten in einem informationssignal |
JP3675256B2 (ja) * | 1999-10-15 | 2005-07-27 | 日本碍子株式会社 | ベクトル信号処理回路 |
DE102006007184A1 (de) * | 2006-02-15 | 2007-08-16 | Dr. Johannes Heidenhain Gmbh | Positionsmesseinrichtung |
JP5141052B2 (ja) * | 2007-03-08 | 2013-02-13 | 日本電気株式会社 | 電源ノイズ測定回路および測定方法 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3961172A (en) * | 1973-12-03 | 1976-06-01 | Robert Stewart Hutcheon | Real-time cross-correlation signal processor |
FR2314538A1 (fr) * | 1975-06-10 | 1977-01-07 | Thomson Csf | Dispositif correlateur et systeme de mesure du retard entre deux signaux comportant un tel dispositif |
US4224679A (en) * | 1978-10-16 | 1980-09-23 | Rca Corporation | Signal correlation means |
JPS61207973A (ja) * | 1985-03-13 | 1986-09-16 | Mitsubishi Electric Corp | 相関式時間差計 |
-
1989
- 1989-12-01 FR FR8915906A patent/FR2655439B1/fr not_active Expired - Lifetime
-
1990
- 1990-11-28 US US07/741,391 patent/US5305243A/en not_active Expired - Fee Related
- 1990-11-28 WO PCT/FR1990/000863 patent/WO1991008493A2/fr active IP Right Grant
- 1990-11-28 CA CA002046652A patent/CA2046652A1/fr not_active Abandoned
- 1990-11-28 JP JP3500673A patent/JPH04505366A/ja active Pending
- 1990-11-28 DE DE91900037T patent/DE69007477D1/de not_active Expired - Lifetime
-
1991
- 1991-06-28 EP EP91900037A patent/EP0473731B1/fr not_active Expired - Lifetime
Non-Patent Citations (1)
Title |
---|
See references of WO9108493A2 * |
Also Published As
Publication number | Publication date |
---|---|
FR2655439B1 (fr) | 1992-05-15 |
EP0473731B1 (fr) | 1994-03-16 |
CA2046652A1 (fr) | 1991-06-02 |
US5305243A (en) | 1994-04-19 |
WO1991008493A3 (fr) | 1996-09-19 |
DE69007477D1 (de) | 1994-04-21 |
FR2655439A1 (fr) | 1991-06-07 |
JPH04505366A (ja) | 1992-09-17 |
WO1991008493A2 (fr) | 1991-06-13 |
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