DE2557906A1 - METHOD OF MEASURING THE FREQUENCIES AND PERIOD DURATION OF NON-COHERENT WAVE PACKAGES - Google Patents

Description

P 543 "

Me / Ca

11/24/75

Patelhold Patentverwertungs- ii.Elektro-iolding AG, Qlanis (Schwe .-. Z)

Yerfalrren ksi * Measurement of the frequencies and period duration incoherent, ^ ISellenpafeeten.

The success; relates to a method for measuring the frequency and period of non-coherent Welienpaücefceüij, ireise bei Bopplergeschwindigfceitsmesseinriefrt-BHsigen. Measurement of the range * of individual periods and image of the prokwert.

In the case of consistent miles, the ifetbode belongs to resource creation Rarely one or more atss-free Fepieeelemja & ervalle soap

longer »zsbbs state of the art. In addition, the frequency of Miles assets by counting the number of MuJLldttreh -

2557306

P 5 * 3

are measured »which are in a certain time interval fall «,

in the case of να »incoherent wave packets, as they occur, for example, with Boppler level measurements, both methods fail or they cannot be used without further ado. Ia the sehweiz-erischeini Patent 521 ^s 59 © lem is to cEess Glad the FreqxEeEismesstmg in inkohäreEifceini MelleEipaketen; an ItäsuiEtg specified _$ in which with a ψοτι the ÄB ^ litnäe of the zss measuring signal derived SeitmariceEtsignal worked vrili * d "This indicates the number of periods lying in a Hessian interval, which changes a b-esfeinmifeeis KLni ~ malen Ämplitwellwert he very have it tem. BeF quotient of this number _s divides dtarch the period, results in the frequency we are looking for.

This known solution has eil However, the power that the SigEialamplitude ndefet in overlapping Mellempaketen · under ueen threshold. needs to sink down «Since the little Weüenpakefce in the; In general, it is not consistent, ie the position of the foot is usually somewhat different

hi the setowreiserisclien patent script a Zeitfebler * from the Size of the temporal phase shift ;. Another disadvantage this solution; When looking at one thing, it turns out very much

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long wave packet, the frequency of which increases steadily. Such a signal can arise with an accelerated measurement object. At the end of the wave packet, the ejector will display the mean frequency of the wave packet, which of course is not satisfactory; rather, a lower value should be displayed at the beginning and a higher value at the end.

The invention is based on the problem of known disadvantages Solutions to avoid. This is achieved in that, in a method of the type mentioned above, by means of a period duration counter shows the duration of each individual period it is measured that the measured value is supplied by means of a comparison logic with one supplied by an averaging device Mean value from a number of accepted and stored mean values by the comparison logic by comparison with older mean values Measured values., It is compared that in the case of a deviation that remains below a certain, predetermined percentage of the new measured value from the last mean value, the measured value is accepted and read into a memory, while at Exceeding said specified percentage due to the deviation of the new measured value from the last mean value the Einspeicherunp; of the new measured value by one of the Comparison logic output signal via a control logic

709822/0822

It is blocked so that when a new measured value is read into the memory, the oldest value in the memory is deleted becomes that after storing a new measured value from the values now available in the memory with the aid of the averaging system a new mean value serving as a criterion for the next period to be measured is formed and that the output signal, which corresponds to the desired Doppler frequency, is obtained by a reciprocal value generator, which forms the reciprocal of the new mean value.

Thus, a period whose deviation from the last mean value exceeds a certain limit and in which in general it can be assumed that they are measured between two zero crossings belonging to different wave packets was not taken into account in the evaluation.

The mode of action should be based on the Pig. I and 2 are explained. In the upper half of the diagram of FIG. 1, the course of a signal over time is plotted (signal amplitude as Function of time t), while below the zero crossings of interest with rising edges with the letters A .., P are designated. This signal consists of two overlapping wave packets. The overlap area is essentially limited to the CD time period.

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P513

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According to the Swiss patent specification 521 * 590, the entire Period from A to P used for frequency measurement, since the signal level in the overlap area is always greater than the threshold is. This threshold value is indicated by the two straight lines S in FIG. According to the invention now checked how much the period AB depends on the mean of the stored values deviates. The period AB is obvious a "normal" period, so it will deviate only slightly from the mean. Therefore the decision logic gets this value accept and save. The same goes for BC, DE and EF. The time from C to D, on the other hand, deviates significantly from the mean and is therefore excluded from further processing.

The reciprocal value generator is normally connected to the output of the mean value generator, but it can also be used as an alternative be inserted between period duration measuring device and decision logic, or the period duration measuring device supplies already has a reciprocal value itself. The mean value is then not, as shown, in the period, but in the frequency space educated.

FIG. 2 shows a block diagram of a device such as is used, for example, to carry out the proposed method

709822/0622

Can be found. The input signal ES reaches the period counter 1, which is supplied to it for the duration of a period Clock pulses CE are counted and the corresponding coded information PD is supplied to an input of the comparison logic 2. For the purpose of synchronizing the comparison process, the comparison logic 2 also receives the input signal ES directly. For comparison, the unit 2 receives the mean value M from the last period duration measured values accepted by the comparison logic fed. As already stated, the logic 2 decides whether the new value PD is accepted and sent to the Memory 3 passed on, or is suppressed as unusable. This depends on whether the deviation of the new Value of the mean value M is smaller or larger than a predetermined one Percentage of M (see above).

In the case of an acceptable value PD, the comparison logic outputs this value to memory 3; the storage and all further operations are brought about by a signal GWA fed from the comparison logic to the control logic 5. This Signal, which is of course only emitted when the new measured value is accepted, initially causes the control logic 5 to Issuing a storage command BS to the memory 3J thus the accepted value GW pending at the memory input is read into the memory, and at the same time the oldest becomes

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The measured value is deleted from the memory, so that the number is always the same is stored.

The changed memory content Spi arrives at the mean value generator 4, which is output as a result of a control logic 5 further command BM forms the new mean value. As can be seen, this mean value is fed to the comparison logic 2 once and is available for comparison with a new measured value; on the other hand, the mean value M reaches the reciprocal value generator b, which, under the action of a third command BR issued by the control logic 5, sets the reciprocal value A of M, i.e. it determines the desired frequency value.

By introducing a new selection criterion in addition to the already known amplitude criteria, it allows this proposed methods of obtaining more accurate readings. The output of the device already delivers during a wave packet the latest value, so there is no need to wait for the end of the wave packet first. This criterion is before especially important with rapidly changing frequencies.

709822/0622

Claims (1)

2557806 Claims l «f ¥ learn for measuring the frequency and FerlGäendauer of non-coherent wave packets, preferably with Dopplergeschwindlgkeitsraesseinrlehtungen» by means of Ättsisessen the duration of individual periods and formation of the reciprocal, characterized in that the Bauer Jessecertier (individual period) wlrd ^ that the measured value is compared by means of a comparison (2) bit of a »mean value supplied by an average value of C ^) from a number of τοπ of the comparison logic (2) by comparing the mean values accepted and stored in a memory (3)» that if the deviation of the new measured value or the last mean value remains below a certain specified percentage, the measured value is accepted and read into memory C3), while if the said percentage is exceeded, the new measured value differs from the last mean value the Einspelcher png of the new measured value is fed by a signal sent to the Tergleleh-slogiic (2) via a control unit C5) that when a new measured value is read into the memory (3), the oldest existing I »memory is deleted of a new measured value 25579 - f - P ams (em now stored in memory values with- help the averaging unit C * O, a new ,, as a criterion for (It is made next serving to be measured Perlodendaaer means value and that the Atisgangsslgnal that entsprlchfe the gesMcaten Doppler frequency _x durcii a Rezi profcwertblldner. (6) is obtained, which forms the reciprocal of the mean value. 2, method according to spoke 1, characterized in that the output of the Pflttelwertbxldner is led directly to the Rezlprokwertblldner (6). 3 · ¥ experience according to claim 1, characterized in that the ßezlprokwertblldner (6) is inserted between the period counter (i> and the Yerglelchslogllc (2)). Α., ¥ _Λ out according to claim 1, characterized in that the Perlodendaoier counter CD with de "RezIprokwertblldneF ζ6} · In a unit is combined ,. 3- Device for carrying out the method according to claim 1 _s dadurett characterized "that the PerlodJendauer — ZSIiler (1) on its Ighlelngang CCE) clock pulses with the order of magnitude of the zxx measuring. Frequencies relatively high frequencies 708822/0622 receives and at its control input (ES) the input signal to be examined, such that the counter (1) at a zero crossing of the input signal starts and the clock pulses during one period until the next zero crossing in the same direction, further characterized in that the count reached is encoded in Form of the comparison logic (2) is fed that a further, the synchronization serving input of the Comparison logic (2) is connected directly to the input signal line (ES) that a third input of the comparison logic (2) is also connected to the output of the averaging unit (ή) that an output of the comparison logic (2) with the read-in input of the memory (3) and a second output with the input of the control logic (5) which control logic is connected via the connection, processing line (GWA) is activated if the comparison logic (2) receives the period duration measured value that has just been checked accepts that the control logic (5) with one of three outputs each with the control input of the memory (3) j the averaging (* ») and the reciprocal (6) is connected and in the activated state emits control commands via the connecting lines (BS, BM, BR), which enable the reading in of an accepted measured value into the memory (3), the formation of the mean value 709822/0822 of the memory content by the averaging device (4) as well as the formation of the reciprocal value of the average value formed controlled by the reciprocal value generator (6). Patelhold Patent utilization and electrical holding AG 709822/0622