TWI593989B - Apparatus and method for correcting an offset - Google Patents

Description

Device and method for correcting deviation

The present invention relates to metrology techniques, for example, to the measurement of the fill level in a tank. In particular, the present invention relates to a deviation determining apparatus, a measuring apparatus, a method for determining a deviation, a computer readable storage medium, and a computer program product.

With respect to certain applications of the time measurement method, it may occur that one of the echo curves selected to determine the deviation of an echo curve no longer exempts interference, such as immunity from noise. In this case, the value of the deviation is erroneously determined and deviates from the true deviation value. Deviation from one of the deviation values actually present may result in inaccuracies or errors in determining a reference line or a normal value. Such inaccuracies may in turn lead to inaccuracies in determining one of the measured values associated with this reference line.

In the document DE 100 44 769 A1, a method for measuring the distance by means of a signal is described, wherein an echo signal is received by a receiver device or by a receiving device, the echo signal being associated with a first reference A pulse is superimposed, and wherein the echo signal is compared with a second reference signal having a second reference pulse for determining a signal transition time.

Often, with regard to the measurement method for measuring the filling level, a reference value must be determined in advance and stored to correct a newly read curve. An empty slot may be necessary to determine this reference value, which must be manually vacated from time to time to adjust the reference curve.

Therefore, one of the motivations of the present invention is to achieve a more efficient amount of signal transition time. Measurement.

Accordingly, the present invention can provide a deviation determining device, a measuring device, a method for determining a deviation, a computer readable storage medium, and a computer program product.

According to an aspect of the invention, a subject matter can be set forth in accordance with an independent technical solution. Other exemplary embodiments of the invention may occur as a result of the subject matter set forth in the accompanying claims.

A deviation determining device can also be adapted to correct a deviation.

According to an aspect of the invention, a deviation determining apparatus is provided which may have a sampling receiver device or a sampling receiving device, a control device and a deviation providing device. The sample receiver device can be configured to receive a time spread sample value of a reflected signal from one of the transmitted signals. In this context, the time-expanded sample values are also understood to include values that have been reconstructed from the sampled values of an echo curve as an analog echo curve. The reflected signal can be composed of a plurality of individual received signals. The transmission signal may be generated by a transmitter device and transmitted or transmitted or transmitted to have a first cycle duration or have a first oscillation time. The transmitter device or the transmission device can be tied to one of the components external to the deviation determining device. To control the external component, the deviation determining device can have an external interface via which signals for and/or from the transmitter device are provided and the external interface can be used to control the transmitter device.

A control device can be configured to control the transmitter device. With regard to this open loop or closed loop control or with respect to such control or regulation, the control device may further be such that one of the time spread sample values of the reflected signal may be one of a predefinable measurement range or a known measurement range Mode setting. The determination of the measurement range may also include the identification of the measurement range. The control device can be further configured to provide a turn-off signal that is outside of the measurement range. The turn-off signal can be at least partially revoked to activate the transmitter device to generate the reflected signal One of the time-expanded sample values may pre-define a static range or an idle range. The measurement range may be one of a time domain or a local domain of an echo curve, wherein the time domain and the local domain may be transformed into each other. Thus, for example, a range can be a chronological interval or a partial interval. The corresponding interval can be repeated periodically in the case of a periodic signal.

The deviation providing device can be configured to: determine a deviation by evaluating at least one of the time-expanded sample values (the value is already within or outside the static range) A value, in particular a value of the amplitude deviation or the time-expanded sample value of the reflected signal, deviates from a normal value, from a zero value or, for example, from one of the zero amplitude values. In one example, the normal value may be an expected amplitude value, an expected value, a set point, or an expected value of one of the receiver output signals, wherein substantially no received signal is caused by the transmitted signal. Can mean a no signal space. In a different example, the normal value can be an expected amplitude value or an expected amplitude value. Thus, the normal value may be substantially only one of the theoretically expected values that do not account for the received signal caused by the transmitter source present under normal conditions. Received signals from a transmission-receiving device itself involving interference that is therefore substantially unswitchable or screened or shielded are not included in this theoretical value.

The deviation determining means may supply a deviation determined based on a deviation from a normal value at an output of the deviation providing means which it contains. A signal having a deviation itself or a correction value supplied at the output of the deviation providing device can be transmitted via the output to an actuator (for example) and/or a digital potentiometer of a deviation control device. For example, one of the bias providing devices can be connected to a digital potentiometer and form a bias control loop. Alternatively or in addition, one of the different output of the bias providing device can be coupled to a digital signal processing device.

In accordance with yet another aspect of the present invention, a metrology apparatus, a metrology system, a metrology configuration, or a metrology setup is illustrated that can include a transmission-receiving device and the discriminating apparatus in accordance with the present invention. In the measuring device, the control device of the deviation determining device can be connected The transmitter device is coupled to, for example, the transmitter device can be acted upon from the deviation determining device. In one example, the transmitter device can be combined with a plurality of other components to form a sensor. In particular, a sensor can include a transmitter device. A measuring device can include at least one transmitter device and one deviation determining device. However, the deviation determining means can also operate as one of the devices external to the measuring means.

According to yet another aspect of the invention, a method for determining a deviation or an amplitude deviation can be illustrated. The deviation that can be determined using this method can be a sample value or a sample amplitude that deviates from one of the normal values.

The method can include receiving a time spread sample value of a reflected signal of one of the transmitted signals, wherein the transmitted signal and thus the reflected or received signal are also transmitted or received by a transmit-receive device for a first cyclic duration. In the method, the method further comprises: at least intermittently or temporarily revoking one of the transmissions that initiates the transmission of the signal, the shutdown signal can be provided and one of the time-expanded samples of the reflected signal can be pre-defined Outside the measurement range. A predefinable static range within the time spread sample values of the reflected signal can be generated by deactivating the transmission of the transmitted signal. Together with the sample values of the measurement range, the static range can result in a composite reflected signal whose cycle duration includes the echo signal and the static signal. The measurement range and the static range may have virtual boundaries that are strung together at the virtual boundaries such that the measurement range and the static range are along a time axis or a local axis of an echo curve Periodically alternate. The boundaries may be located at points corresponding to an even multiple of the first cycle duration. However, it can also be located at any other point. In one example, the cycle duration by which the measurement range alternates with the static range may correspond to one of the turn-off signals.

The method for determining a deviation value may additionally include determining a value of the deviation of the time-expanded sample values of the reflected signal from a normal value. At least one sample value located within a static range generated by the deviation determining means can be determined for use in determining the deviation. A boundary condition that should actually result in one of the normal values can be applied. When the conditions of the boundary conditions are effective, The deviation of the measured echo curve from the expected echo curve can be determined by actually determining the reflected value.

In addition, it is conceivable to supply the value of the determined deviation as one of the outputs of the method.

In accordance with yet another aspect of the present invention, a computer readable storage medium having a code that, when executed by a processor, performs a method for determining a deviation.

In accordance with yet another aspect of the present invention, a computer program product can be specified that, when executed on a processor, can instruct the processor to perform a method for determining a deviation.

A deviation determining device may be capable of receiving a reflected signal or a received signal provided in any form. The reflected signal may initially be generated by a transmitter device that transmits a transmission signal. For example, the transmitter device can transmit one of a pulse signal or a transmitter with a predefinable first cycle duration. The pulse signal can have a fixed or variable burst frequency and a repetition frequency and a burst of one of the predefined first cycle durations. In a different example, the pulse signal can have a single pulse of a repetition frequency and a predefinable first cycle duration. The deviation determining means can receive the received signal by means of a receiver device (for example, an antenna). The receiver device can be part of a transmit-receive device. The receiver device can also include the sample receiver device. The reflected signals received by the receiver device with respect to the respective reflectors can be analyzed by means of a downstream evaluation or evaluation device, for example, implemented by an electronic device or by an electronic system.

When the transmission signal is transmitted with a first cycle duration, the reflected signal may have substantially the same first cycle duration. The time spread sample values may be generated by signal conditioning from a plurality of periodically repeated received signals. The number of periodic signals used to generate the time-expanded samples of the reflected signal can be determined to result in an extended representation of one of the reflected signals or a time spreading factor of an extended representation.

The time spread sample values may be sequentially sampled by a second cycle duration A periodic signal appears. For example, the received signal can be a periodic signal that is sampled. Basically, sequential sampling may not be used for digitization but for time expansion. Thus, in one example, a time-expanded echo curve can be generated from the sampled values.

The time-expanded echo curve of the reflected signals has substantially the progression or shape of the periodically repeating, actually received echo curve. However, one of the time domains can be expanded by means of time expansion, the result of which is a possible scaling of one of the relationships between time and distance. The time-expanded reflected signal can be provided as an analog curve. However, after digitization, one of the discrete values of the time-expansion analog reflection curve can also be generated, whereby digital signal processing of the time-expanded samples of the reflected signal can be achieved, for example. The time extension analog curve can be sampled for a third cycle duration. This sampling may result in substantially identical or shifted interpolated points, sampling points, support points or nodes from which the analog time expansion curve is generated. By using a signal having a third cycle duration, a more accurate or coarsely resolved interpolated point can occur than in the case of a second cycle duration.

In another example, the step of reconstructing an analog echo curve may be skipped, and the interpolated points that are already present due to sequential sampling and separated by the second cycle duration may be used as a starting value for digitization. .

In yet another example, the third cycle duration can have the same value as the second cycle duration.

The time-expanded samples of the reflected signal may represent an interpolation point of a waveform or a curve progression, the values substantially reflecting the discrete behavior of the reflected signal and the interpolated points may have a time interval of a sampling signal . For example, this time interval or time distance can be a second cycle duration. The second cycle duration may be greater than the first cycle duration, which means that the corresponding high number of iterations of the sampling operation or sampling action are periodically repeated to receive the received curve over an extended time scale map. The smaller the time difference between the cycle durations, the finer the time and/or local resolution of the time-expanded sampled echo curve, or The closer the insertion points can be to each other. When the transmission signal is generated substantially periodically, a periodically operating reflected signal or a periodically reflected signal may be generated.

To now reach a deviation determination, the described deviation determination device can provide a signal that enables the transmitter to be turned off or revoked for a predefinable time. Turning off or deactivating the transmitter or transmitter device turns off the transmission signal, which signals the cause of the reflection. The source of the turn-off signal causes the existing reflection to elapse, and there is substantially no more reflected or reflected signal that can be received after a certain waiting period or after a certain waiting time. If the deviation determining device is used in a quasi-measurement instrument, turning off the transmitter device can result in substantially no echo or reflection in the interior of a slot. Thus, by turning off the transmission signal, the deviation determining means can generate a predefinable or defined static range in the time-expanding analog reflection curve and thus also in one of the corresponding sampling time-spreading echo curves. In the reflection curve actually received, the turn-off can form an appearance of one of the periodic signals that can be interrupted during the off time. In other words, the measured reflected signal can be adjusted to a substantially measured reflected signal (stable state) corresponding to a static value in the actual measurement environment. In other words, the measured reflected signal can form an instantaneous oscillation to achieve a reflection or steady state of the actual measurement. Although the transmission signal is turned off, the adjusted actual reflected signal or the actually reflected signal existing in the steady state after the transmission signal is turned off may be shifted from the expected normal value or from the expected normal value according to the deviation. . In other words, the amplitude value of the reflected signal can be continuously or linearly shifted according to the deviation value. Thus, a particular received value, a normal value, or a desired value can be expected when a transmitter device is turned off. However, the following may occur: although there is a boundary condition that should cause this normal value, the expected normal value cannot be determined in the actual environment, because the interference may cause the actually measured reflected signal to deviate from the expected normal value. . However, if a substantially constant overlap of the interference of the received signal is assumed, it can also be assumed that the reflected signal actually received when the transmitter device is turned on also deviates from the interference-free reflected signal to be expected.

Combining the resulting reflected signal and, in particular, with respect to the reflection curve produced therefrom or The echo curve, "periodic" can mean that a regular echo curve is generated from a transmission signal that is transmitted periodically. The transmission signal periodically transmitted may have a certain periodicity. The shape or progression of the echo curve can be substantially dependent on the physical condition of the signal propagation path and the distance of a reflector from the transmitter device. In other words, this may mean, for example, that when a deviation determining device is used to perform a level measurement in a tank or in a container, the shape or progression of the periodic echo curve may depend on the object in the tank or The filling level of the installed components and the filled goods. For example, such mounted components can be mounted to a mixer or ladder in a tank. When the echo curve or the amplitude of the reflected signal is plotted over time, the reflection of the object is significant. In this connection, a stuffed cargo may mean an item or material that is to be judged in a tank to fill its level. It can be a fluid, that is, a gas or a liquid, a solid or a solid.

The term "periodic signal" may mean obtaining a measurement range from a reflected signal at periodic intervals, in which a reflection curve is generated inside a filling cargo tank, and although the transmitter is turned off, it appears A static range is produced by having turned off the transmitter device and recording the signal. Therefore, a boundary may occur between a region of the echo curve in which the reflected signal is expected and should be evaluated, and a region in which the static behavior of a measuring device should be determined by means of the deviation determining device.

During the static phase, the phase during which the transmission signal is blocked or not generated, the effect of reflection by a transmitted signal should be substantially discarded to determine the effect, influence or impact of the receiver on the received signal. One of the time-expanded samples of the reflected signal may have a plurality of interpolated points. The plurality of interpolated points can be considered to be a set, a group, or a certain amount of interpolated points. In this set of interpolated points, the static range may be defined as one subgroup or a subset of adjacent interpolated points outside the range in which the reflected signal is typically present. The subgroup interpolation points belonging to the measurement range should form a different separation subgroup interpolation point.

A measured echo curve or resulting echo curve may consist of an overlap from the influence of the reflection (i.e., the expected echo curve) and the interference effect. If interference affects (specifically, The interference effects of the receiver are known, and the interference corrected echo curve or the substantially expected echo curve can be determined based on the measured echo curve. Since the sampling device of one of the deviation determining devices can also function during the static time, it can be determined that, without the influence of reflection, the echo curve is caused to deviate from a specified desired static value and normal value during the measuring phase. Or the effect of a zero amplitude receiver device. Due to the influence of the interference signal or the noise signal from the receiver, the echo curve actually determined can be shifted with respect to the expected echo curve. This static range can also be referred to as a static time or static phase.

A deviation (specifically an amplitude deviation) may be substantially constant or fixed over a time interval or within a spatial interval of linearly shifting a amplitude of a received signal from a static value, as a result of this, Producing an error or a deviation of the acquired reflection curve or echo curve from the expected echo curve. If the received signal is free of interference, the expected echo curve will be measured. This ideal echo curve should be approximated by deviation elimination. Since the amplitude value of a reflected signal can often be represented by a abscissa, an x-axis or an x-coordinate as a time axis or a local axis in a Cartesian coordinate system, the deviation can basically mean One of the coordinates is constantly shifted. Therefore, it may be possible to determine the deviation or deviation value by means of the deviation determining means and generate a correction signal. This correction signal can be provided and used to approximate the measured echo curve to the interference-free echo curve to be expected. This makes accurate measurement easier.

According to an exemplary embodiment of the present invention, the time interval or a time distance of the time-expanded sample value of the reflected signal is a second cycle duration or a third cycle duration, wherein the second cycle duration or the third The cycle duration can be greater than the first cycle duration. The choice of the time interval at which a received echo curve is sampled may result in an echo curve that is periodically generated by interpolation of the interpolated point or sampled value. The retrace of the echo curve produces a time-expanded representation of one of the echo curves. The closer the second cycle duration is to the first cycle duration, ie the smaller the difference between the two cycle durations, the more detailed the echo can be traced back in the time extension zone or in the time extension domain Curve; however, in the description The more cycle durations you can take before drawing a complete echo curve.

According to still another exemplary embodiment of the present invention, the duration of the turn-off signal or the cancel enable signal may correspond to an integer multiple of one of the first cycle duration or period.

The duration of the turn-off signal may state that a transmitter device may not generate a transmission signal or may not generate a time domain, a time range, or an interval. This can result in receiving static values. The static value may be generated with substantially no reflection such that the receiver device or receiver may only receive interference from the environment during the static phase. For example, environmental impact can be receiver noise or environmental noise. The duration of the turn-off signal determines the duration of one of the static intervals on the time axis. This duration of static or static duration can be transformed into a local range, static range. Thus, the value received during the application of a turn-off signal at a sampling receiver device can be in the static range or for a static duration. Due to the limited duration, the static range defines a time interval or a segment, in particular a segment of a local scale. Due to this division of the scale, the static interval can be considered as one of the relevant scales surrounded by other ranges (which can be considered as other ranges than the static interval). These external ranges can include static intervals. The received value received when a transmitter device is active (i.e., when a transmitter device is not turned off) may be in such an external range outside of the static range. The received value received when a transmitter device is deactivated (i.e., when a transmitter device is turned off) may be in a static range.

The term "domain" or "range" can be used to describe a time domain as well as a local domain, wherein substantially two domains can be converted into each other by including a signal propagation speed, a substantially speed of light, and a time spreading factor.

The range outside the static range can be substantially measured. This measurement range may set forth a range of measurements that may be of interest for the reflected signal. The length of the measurement range can be specified according to the device implementation or depending on the device design (for example, a sensor length, a probe length, and/or where an application of the metrology device will be used). The height of the trough or the relative permittivity (ε _r ) of the filled cargo can play a role in the application. In addition, the length of the measurement range can be affected by a planned safety range. This range of safety may be within a range of measurements provided to ensure that all slot related reflections are also truly obtained. In one example, the measurement range may correspond to an actual slot length, that is, to an echo in which a local domain of one of the echo signals is expected to be substantially for a specified or predefined slot height or slot length. The time domain of the curve. Thus, the time-spread reflected signal can retrace a change between the measured range and the static range, wherein the interface or transition between the two ranges can be referred to as a boundary or range boundary.

Thus, starting from a measurement range, a static range can be located after a measurement range when viewed as being in a time domain. The static range can be further away from a transmitter device along a local axis. It may be such that the deviation determination is not immediately started at the boundary of the range but may initially wait for a decidable time or a safety interval before determining the deviation value. However, due to sequential sampling, the security interval can become significantly shorter than if a non-time spreading signal has been used.

The safety interval can be chosen to be extremely short. In one example, a static range of 1 m or a corresponding transformed time period may be the result of selecting a short interval of a safety interval or a safety range regardless of the length of the measurement range. The following situation can be considered as an aspect of the present invention: forming a deviation determining means for generating a turn-off signal which causes or causes one of the static ranges of one of the deviations of 1 m or less to be determined. The length of the measurement range can be variably adjusted. In a different example, the length of the static range can be 1 m or 2 m or any other value between 1 m and 2 m.

Therefore, it is not necessary to add or follow a static range depending on the measurement range, since the static level can occur substantially immediately if the transmitter is deactivated. The measurement range and the length of the static range can be specified independently of each other. A period in which the reflection is attenuated may occur because the non-time-spread reflected signal typically must decay or decrease over the duration of the plurality of first cycles. Therefore, the time-spread reflected signal generated by sampling requires the same time to attenuate, wherein due to time expansion, the decay time is negligibly small relative to the time in which the static level exists or the time in which the measurement range exists. Very small. For example, due to time expansion, the decay time is a few microseconds for the measurement range or the static range. The time can be in the range between 1 millisecond and 100 milliseconds.

According to still another exemplary embodiment of the present invention, the predefinable measurement range may depend on a slot height.

To be able to account for a variable slot height, the deviation determining means can provide a means by which the user can specify and adjust the slot height. The measurement range that can vary depending on the application, but which can substantially correspond to the slot height or a corresponding comparison value, can also be specified via this setting device. The control device can include this setting device.

According to still another exemplary embodiment of the present invention, the deviation determining means and, in particular, the deviation providing means may be arranged in one of the following manners: by averaging a plurality of sample values determined from the static range in the deviation providing device The value of the time-spread sample value of the reflected signal from the normal value. There is a deviation of the time-expanded sample value from one of the normal values.

In the static range, with regard to a high degree of probability, it can be assumed that all effects of the previously generated reflection of a measurement range have been attenuated such that it can no longer have any effect on the determination of the deviation. It may be possible to implement an accurate deviation determination by this selection of the time or position of the time point, the deviation within the static range. The static range can be generated at any position within the periodic reflection curve or echo curve and at any interval length by undoing the activation of the transmitter device during this interval. According to yet another aspect of the invention, the static range is directly selected after the end of the measurement range.

According to still another exemplary embodiment of the present invention, the deviation determining device may have a selector device that is arranged such that it supplies one of the measurement ranges at a first output of the selector device Time spread sample value. Additionally, the selector device can be configured such that it supplies at least one sample value that is determined within the static range and thus is outside of the measurement range to the deviation providing device via a second output of the selector device.

With such a selector device, it is possible to transfer the received value of the reflected signal to a different signal processing device of the deviation determining device depending on a switching state.

For example, the reflected value or the sampled value determined within the measurement range may be forwarded to a deviation correcting device in a first switching state, and the received signal value may be directly provided as a practical determination via the offset correcting device. Measured value. The received signal value may also be exempt from the offset in the offset correction device and provided as a corrected echo curve after an offset correction. When the corrected echo curve is supplied, a deviation determining means may be provided to determine whether a deviation correction is necessary, and if it is necessary, the deviation value is included. If there is no such deviation correction system, the received echo curve can be directly provided. Providing one of a distance or a fill level from the corrected echo curve due to a determination of a time or distance between a reference signal or a transmitted signal and a position of the reflected surface of the filled cargo determined from the reflected signal Measurement value.

After switching to a second switching state, the selector device can forward the value received during a static range or within a static range to the deviation providing device. The deviation provides that the device can determine the current deviation value from a value within the static range and can make this current deviation value available to, for example, the deviation correction device. In the second switching state, an average deviation value can be determined by averaging over a longer period of time to increase accuracy.

Therefore, the selector device can achieve classification of reflected signals. The sampled value of the reflected signal occurring within the measurement range is forwarded to the deviation correcting device due to the first switching state. The sampled value that has been received in the static range can be forwarded to the deviation determining device. Therefore, the total set of sampled values of the reflected signal over a period of time can be divided into a subset of sample values of the static range and a subset of sample values of the measurement range. In particular, the selector device can ensure the specification of the range boundary between the measurement range and the static range by means of switching. With regard to this specification of the range boundary, the selector device can be substantially coupled to a control device that can also generate a shutdown signal for the transmitter device.

According to still another exemplary embodiment of the present invention, the deviation providing device may be configured to use a time-expanded value of the reflected signal from a normal value to deviate or deviate from the determined value, before sampling the reflected signal or in the digitalized reflection Before the signal, the reflected signal is Deviation correction. Alternatively or additionally, the bias providing means can be arranged to use the determined value of the deviation to perform a deviation correction on the reflected signal after digitizing the reflected signal. To distinguish between sampling for the purpose of time spreading, sampling the reflected signal for digitization purposes may be referred to as A/D (analog/digital) conversion or digitization. A sampled signal having one of the third cycle durations can be used for digitization. The third cycle duration for digitization may be equal to, or may be different from, the second cycle duration for time-expanded samples.

Prior to digitizing the reflected signal, there may be a time-amplified reflected signal as a substantially analog reflected signal or as an analog echo curve.

After digitization, for example, by means of a analog/digital converter (A/D converter), the discrete value of the analog time-expanded echo curve can illustrate a discrete time-expanded echo curve. Unlike the analog value, the discrete values of the discrete echo curve can be corrected by calculations by means of a digital signal processing device. For example, a microprocessor and a number of digital signal processing methods can be used for this calculation.

One of the deviation corrections on the analog side (i.e., prior to the digitized echo curve) may be by means of a hardware device such as, for example, an analog actuating element or a digital potentiometer. A analogy correction can also be combined with a digital correction to have a better effect on the reflected signal to be corrected.

According to still another exemplary embodiment of the present invention, the deviation determining device may include an offset correcting device, wherein the offset correcting device is configured to correct a time-amplified sample value of the reflected signal to provide an interference correction by one of the value correction of the deviation The reflection curve or the echo curve corrected by interference. The ideal non-interference echo curve can be approximated by correcting or cleaning the interference in the echo curve. In this context, "correction" can also mean "clearing" or "cleaning up".

According to still another exemplary embodiment of the present invention, the deviation determining device may include an undoing device. For example, the undo device can enable a user to The turn-off signal is transmitted at the point in time (for example, even within the measurement range). Therefore, the undo boot device can overwrite the control device.

In other words, the undo start device may make it possible to perform a deviation measurement immediately, regardless of whether the end of the measurement range within the echo curve has been reached.

In accordance with yet another exemplary embodiment of the present invention, the time spread sample values of the reflected signals may be generated by sequential sampling and/or by digitization. Sequential sampling may correspond to performing a cross correlation.

The generation of time-expanded sample values can occur essentially in two phases. In a first phase, a time-expanded analog signal or a time-expanded analog echo signal can be generated from a periodic analog reflection curve by means of cross-correlation or sequential sampling. An A/D converter can then be used in a second phase to discretize or digitize the time-spread analog echo signal. Therefore, the time spread sample value of the reflected signal is then available. In one example, the deviation determining means can have means for generating a time spread sample value based on the two-stage procedure. However, time spread sample values may also be provided by an external transmitter device.

According to still another exemplary embodiment of the present invention, the measuring device may be selected from one of the group consisting of: a quasi-measuring instrument, a limit level measuring instrument, and a time domain reflection. Meter, a reflection measuring instrument and a measuring instrument based on the principle of guided microwave.

A computer readable storage medium can be a floppy disk, a hard disk, a USB (Universal Serial Bus) storage medium, a RAM (random access memory), a ROM (read only memory), and an EPROM. (Can erase programmable stylized memory). A communication network such as the Internet can also be considered as a computer readable storage medium for uploading or downloading code.

Accordingly, the present invention is directed to an apparatus for implementing the concept of transforming a periodically received echo curve into a time spread range and producing a static range. Due to time expansion, A suitable range can be utilized in which a transmitter can be turned off and in which the reflected signal can be expected to decay very rapidly to determine a bias value by means of an active receiver or by means of an active receiver device or by means of an active receiver device. This offset value can be adapted to shift the received echo curve affected by the interference such that it approximates a desired echo curve. This desired echo curve will occur if a reflected signal has been received by means of a substantially non-interfering or ideal receiver device. When determining the desired echo curve or the interference corrected echo curve, a shift of the received static value from a desired static value, from an expected ideal value, or from a normal value may be considered. In other words, the deviation of the actually measured static reflection curve from the expected static curve to be expected can be measured during the static range. The desired static curve may be a curve whose shape, progression or characteristic is known in advance. For example, it is known that it can be considered to be the shape of a zero amplitude curve of one of the desired static curves, and the shape reflects the expected echo shape because it is in the absence of any reflected or received signal or Appears when the transmitter is turned off. An echo curve containing reflection may not be suitable as a desired static curve. Therefore, one of the reflection curves of an empty slot should not be used as a reference curve or a desired static curve. Rather, the desired static curve should have a substantially constant shape under known boundary conditions such that it can be substantially assumed that after setting the boundary conditions, the desired shape will be produced and any deviation from the expected shape will be Indicates an interference.

It should be noted that various aspects of the invention have been described with reference to the various subject matter. In particular, certain aspects have been set forth with reference to the device technical solutions, while other aspects have been set forth with reference to the method technical solutions. However, an expert may infer from the above description and the following description that, except for any combination of features belonging to a subject matter category, unless otherwise stated, the features of the different subject categories will be considered as disclosed herein. Any combination between the two. In particular, a combination of features of the device technical solution and features of the method technical solution should be disclosed.

100‧‧‧ slots

101‧‧‧Filled goods

102‧‧‧Transmission-receiving device

103‧‧‧Transmission signal

103'‧‧‧ Transmission signal

104‧‧‧Slot bottom

105‧‧‧Filling the surface of the cargo

106‧‧‧ reference line

107‧‧‧Deviation Judging Device/Microcontroller μC/Microprocessor μC/μC/Processor/ Microcontroller

108‧‧‧Interface/standard interface/external interface

109‧‧‧Measuring device

110‧‧‧Antenna

110'‧‧‧Coupling device

130‧‧‧Guide

201‧‧‧ lead

202‧‧‧ lead

203‧‧‧ lead

204‧‧‧Sampling Receiver Device

205‧‧‧Selector device/segment device/separation device

206‧‧‧Control device/sampling control device/sampling controller

207a‧‧‧ first output

207b‧‧‧second output

208‧‧‧ Deviation providing device

209‧‧‧Error Correction Device

210a‧‧‧ first output

210b‧‧‧second output

211‧‧‧Averaging devices/average devices

212‧‧‧Final processing device

213‧‧‧ Output

214‧‧‧Revocation of the start device

301‧‧‧Actuating element

302‧‧‧Transmitter

303‧‧‧ Analog/Digital Converter

304‧‧‧Storage device

305‧‧‧Transmission and Receive Separator/Transmission-Receiver Separator

306‧‧‧Bidirectional input and output

307‧‧‧ output

308‧‧‧Mixer/Relainder/Sampler

309‧‧‧Local Oscillator (LO)

310‧‧‧Mixer output

311‧‧Amplifier/amplifier devices

312‧‧‧ lead

313‧‧‧Connect

314‧‧‧virtual boundary

320‧‧‧Lead/feedback leads

400‧‧‧reflected signal

401‧‧‧ time scale

402‧‧‧reflected signal

403‧‧‧ normal value

404a‧‧‧ signal curve

404b‧‧‧ signal curve

404c‧‧‧ signal curve

405‧‧‧ border

405'‧‧‧ border

406‧‧‧Amplitude deviation

407‧‧‧ echo curve

408‧‧‧ deviation curve

409b‧‧‧sampled value

409c‧‧‧sampled value

409d‧‧‧sampled value

409e‧‧‧sampled value

409f‧‧‧sampled value

410‧‧‧Control range

420‧‧‧ ordinate

421b‧‧‧sampled value

421c‧‧‧sampled value

421d‧‧‧sampled value

421e‧‧‧sampled value

421f‧‧‧sampled value

501‧‧‧pulse generator

502‧‧‧clock oscillator/oscillator

700‧‧‧Switching on/off switching devices/switches

A‧‧‧ analog echo curve

B‧‧‧ time extended analog echo curve

C‧‧‧ Discretized echo curve

H‧‧‧ slot height

T1‧‧‧cycle duration

T2‧‧‧cycle duration

Tx_On‧‧‧ control signal

I‧‧‧Measurement range

II‧‧‧Static range

Other illustrative embodiments of the invention are set forth below with reference to the drawings.

1 shows a measurement configuration or a measurement setup for level measurement by free field propagation of a transmission signal, in accordance with an exemplary embodiment of the present invention.

1a shows a measurement configuration or a measurement setup for level measurement by propagating a transmission signal according to a guided microwave principle, in accordance with an exemplary embodiment of the present invention.

2 shows a block diagram of a deviation determining apparatus in accordance with an exemplary embodiment of the present invention.

3 shows a block diagram of a measurement device including a transmission-reception device and a deviation determination device, in accordance with an exemplary embodiment of the present invention.

4 shows a schematic representation of the generation of time-amplified sample values of a reflected signal in accordance with an embodiment of the present invention.

5 shows a block diagram of a transmit-receive device in accordance with an exemplary embodiment of the present invention in which the transmit-receive device can be turned off by deactivating an oscillator.

6 shows a block diagram of a transmit-receive device in accordance with an exemplary embodiment of the present invention in which the transmit-receive device can be turned off by deactivating a pulse generator.

Figure 7 shows a block diagram of a transmission-reception device in accordance with an exemplary embodiment of the present invention in which the transmission-reception device can be turned off by means of an on/off switching device.

FIG. 8 shows a flow chart of one method for determining a deviation, in accordance with an illustrative embodiment of the present invention.

9 shows yet another flow chart of a method for determining a deviation in accordance with an embodiment of the present invention.

The illustrations in the figures are schematic and not to scale. In the following description of FIGS. 1 to 9, the same reference numerals are used for the same elements or elements corresponding to each other.

1 shows a measurement device 109 for level measurement in accordance with an exemplary embodiment of the present invention. Regarding the level measurement, the filling should be determined as accurately as possible in a slot 100. The position of the goods 101. In this case, the slot 100 has a slot height h measured substantially parallel to the direction of signal propagation. A mounted component (not shown in Figure 1) that can affect the reflective behavior can be present in the slot. To determine the slot height h, a transmission signal 103 is generated by a transmission-receiving device (or sensor) 102 that is transmitted in the direction of a slot bottom 104 opposite the transmission-receiving device 102 and on the slot bottom 104. Or on the fill cargo surface 105 when there is a fill cargo 101. The reflected signal is received by the transmit-receive device 102 having a transmit and receive splitter 305 and/or a transmitter 302 and further processed. Turning off the transmitter is understood to mean turning off the transmitter 302 of the transmission-receiving device 102. It is still possible to receive a signal by means of the receiver portion of the transmission-reception device 102. During further processing, the reflector is determined to be one of the distances from one of the reference lines 106 of the transmission-receiving device 102 or to fill the cargo surface 105 or the bottom of the slot, based on the determined transition time of the transmitted signal and the reflected signal in the measurement device 109. 104 The distance from the reference line. The reference line can be determined by the mounting position of the transmission-reception device 102 and, in particular, by the mounting position of the antenna 110.

However, when a reflected signal is received, interference may occur in the form of a deviation of one of the reflected signals caused by the addition or application of an error value due to environmental influences. Due to the deviation, the measured reflected signal does not correspond to the expected reflected signal but corresponds to one of the substantially shifted constant offset values. The deviation determining means 107 is to be used to compensate for this shift, deviation or deviation from a reference value. For example, the reference value can be a zero amplitude and is also an echo curve to be expected. To compensate for the deviation, the deviation determining means 107 determines the deviation value and takes the deviation correction. The offset correction can have an effect that substantially defines a reflected signal that is close to one of the expected desired reflected signals. The transmission-reception device 102 is connected to the deviation determination device 107 via an interface 108 and together forms the measurement device 109. The connection between the deviation determining device 107 and the transmission-reception device 102 is, for example, via a busbar interface, via an I ² C (internal integrated circuit), via an SPI (serial peripheral interface), or via another Formed in a series or parallel interface.

Even in FIG. 1, the deviation determining means 107 is shown as one of the devices external to the transmitting-receiving device 102, and the deviation determining means 107 can be integrated in the transmitting-receiving device 102. By providing a standard interface 108, the deviation determination device 107 can also be retrofitted into an existing transmission-receiving device (or sensor) 102 to also achieve offset correction in the already installed transmitter device.

A deviation typically represents one of a desired value or a shift in one of the characteristic curves. In the current case of deviation correction of an echo curve or reflected signal, a deviation is intended to illustrate that one of the echo curves is determined substantially without interference and one of the echo curves is determined in the case of interference. An amplitude deviation or a difference. The deviation shift of one of the echo curve or the reflected signal may also occur due to physical influences such as temperature fluctuations (for example, absolute temperature), due to electromagnetic interference, due to the setting of the receiving electronics, and due to the influence of corresponding noise. These effects can have an effect on both the transmission path of the signal and on the receiving electronics.

Figure 1a shows one measurement configuration using a guided microwave principle for fill level measurement. The setting of this measurement configuration substantially corresponds to the setting from the measurement device 109 of FIG. The antenna 110 is replaced with a coupling device 110' that is configured to couple the transmission signal 103' to the guide 130. The guide member 130 can be configured as a strip probe, a metal cable, a rod, a waveguide, or a coaxial cable. The transmitted signal 103' propagates along the guide 130 rather than in the free field. The description for the measurement setup with respect to the free-field propagation from Figure 1 applies correspondingly to the measurement setup from Figure 1a using the guided microwave principle, even if only the free-field propagation is discussed in the description.

Deviations due to interference should be compensated or corrected as it can result in a limitation on system sensitivity. System sensitivity is specified by the minimum echo still to be detected. In this case, an echo means that the amplitude received by one of the echo curves is offset from a specified reference value or one of the normal values along the direction in which the ordinate of the coordinate system representing one of the echo curves. For example, the reference value is a zero amplitude and can coincide with the abscissa of the coordinate system. Normal value It is defined as the amplitude value that will be reached or adjusted in the absence of any or any interference and without the receiver receiving any received signals.

Since the deviation can cause deviation from one of the normal values and the deviation (for example, due to the variable that can be changed in chronological order) itself can be time dependent when the temperature fluctuates, one of the deviations can be recognized as an echo and in which The detection of an echo and thus the erroneous output of one of the measuring devices 109 can also result in a situation where there is no echo.

When the system sensitivity is specified by the minimum echo still to be detected, one of the echo signals may cause a misunderstanding. This is because a detection curve is often overwritten for the purpose of echo detection. Wave curve. The detection curve can be generated in a number of different ways (eg, as a plurality of straight lines extending parallel to the x coordinate, other rising or falling straight lines, single or multiple curved functions) or can be generated from one of the echo curves stored at a certain point. For example, the stored echo curve can be determined by measuring an echo curve in an empty slot, wherein a filter method such as a high pass, low pass or band pass filter can be applied to an echo curve. The stored echo curve is formed.

The detection curve can also serve as a highly abstract echo curve for one of the threshold curves for echo detection. The closer the curve can be placed to the desired echo curve (i.e., the better the echo curve with one of the low deviations is determined), the smaller the echo that can still be detected.

The closer the detection curve is to the static value of the echo curve, the more echoes can be detected and the more sensitive the system becomes to echo detection. When selecting a detection curve, try to maintain the minimum distance between the expected echo curve and the detection curve. The distance between the curves is the detection threshold. The lower this is selected, the smaller the echo that can still be recorded or temporarily stored. For example, the detection threshold can have a value of 5 mV. In one situation in which there is substantially no interference at all, the detection curve may even coincide with the normal value curve or even with a zero line and may be in a straight line. This means that each deviation from the zero line identification in an echo curve can be interpreted as an echo. However, often, the detection curve is substantially parallel to the normal value curve or one of the zero amplitude lines because there are essentially some shifts that can always exist. Therefore, until the echo has a higher than the detected The echo height is detected by one of the lines or the signal amplitude. Since there may be a positive offset and a negative offset with respect to an echo curve, two detection curves (one higher than the normal value curve and one lower than the normal value curve) are used when necessary and these curves basically explain One tolerance range for the normal value curve. The detection curve can be divided into various regions with different detection thresholds. For example, it is possible to set a threshold in the short range that is higher than in the long range. The short range can be located at most 0.5 m away from the reference line 106. The distance between the detection curve and the non-interference echo curve is specified by one of the expected deviations to be determined on the determined echo curve. The smaller the deviation becomes, the smaller the distance between the non-interference echo curve and the detection curve. The smaller the distance, that is, the lower the deviation to be expected due to, for example, the lower it will be corrected, the higher the sensitivity of the overall system.

2 shows a block diagram of a deviation determining device 107 in accordance with an exemplary embodiment of the present invention. The deviation determining device 107 has an external interface 108 that can be connected or tied to a transmission-receiving device 102 (not illustrated in Figure 2). For example, interface 108 includes three leads 201, 202, 203 that provide a connection to transmit-receive device 102. The interface 108 shows a first lead 201 through which a correction value for compensating for one of the deviation values determined by the deviation determining means 107 can be supplied to the actuator. For example, the actuating element can be used as a one-digit potentiometer for the deviation control or offset correction of the analog echo curve B. The interface 108 also includes a second lead 202 that can be replaced via a second lead 202 with a control signal having a name Tx_On by a transmit-receive device 102, depending on the signal that causes the transmitter 302 to be turned "on" and/or "off". Use this signal as defined. Therefore, a turn-off signal for generating a static range can be supplied to the transmission-reception device 102 via this lead 202.

Interface 108 also includes a third connection that is configured as an input. Lead 203 is connected to sampling receiver device 204. Via the sample receiver device 204, an echo curve (i.e., for example, a time spread sample value of the reflected signal) and a deviation curve can be received or read by the deviation determining device 107.

The leads 201, 202, 203 of the interface 108 can be implemented as separate leads or by a virtual channel of a bus bar protocol. The sample receiver device 204 can have a selector device 205 that is driven by the control device 206, the sample control device 206, or the sample controller 206. The selector device 205 has a first output 207a and a second output 207b. In a first switching state, the selector device 205 can supply the sampled values of the echo curve within the measurement range via the first output 207a. In a second switching state, the selector device 205 can cause the sampled values of the echo curve in the static range to be available via the second output 207b.

The entire echo curve or the entire reflection curve that has been sampled has two ranges. In one aspect, the entire reflection curve has a measurement range that contains measured reflectance values for existing reflected signals. On the other hand, the entire reflection curve has a range of deviation, a static range or is set forth to account for deviations in the portion of the overall reflection curve recorded when the transmission-receiving device 102 and, in particular, one of the transmission-reception devices 102 are turned off. A range of curves. The transition between the switching states can be synchronized with the range boundaries between the measurement range and the static range.

The deviation curve can be passed to the deviation providing device 208 via the second output 207b. The echo curve or measurement range can be passed to the offset correction device 209 via the first output 207a. Thus, the selector device 205 allows all of the reflected signals to be segmented into echo curves and deviation curves as well as different ranges to be delivered to different signal processing devices. The echo curve includes a subset of the sample values that exist within the measurement range. The deviation curve includes a subset of the sample values that exist within the static range. Thus, by means of the selector device 205 it is ensured that substantially only those sample values that have been recorded or received during a period or a time interval of the shutdown of the transmitter are available to the deviation providing device 208. The segmentation device 205, the separation device 205, or the selector device 205 may further ensure that substantially only the sample values that are determined when the transmitter device is also active and that are therefore expected to be echoed and reflected within the slot are supplied to the deviation Correction device 209.

The deviation providing device 208 can also be described as a deviation determining device. The deviation providing device 208 can determine the deviation value based on a deviation of the received deviation curve from a normal value or based on a deviation of the sampling value of the static range from a normal value. In particular, the deviation providing device 208 is available One of the deviation values used for one digit or calculated deviation correction and one deviation value for one type of deviation correction.

The signal for one of the analog deviation corrections can be supplied to the transducer device (not illustrated in FIG. 2) on the analog side via the second output 210b of the bias providing device 208 via the lead 201 of the interface 108. Therefore, the second output 210b supplies one of the signals for the offset correction before digitizing by means of the A/D converter or on the analog side.

A digital offset value can be determined for one digit offset correction. The digital offset value may be supplied to the offset correction device 209 via the first output 210a of the bias providing device 208. The offset correction device 209 can correct the received echo curve (ie, the sampled value of the reflected signal within the measurement range) using the digital offset value (ie, by the value of the offset in the case of the transmitter system) and It is passed to the averaging device 211. The signal at the first output 210a is used for digital offset correction, for example by a processor. The averaging device 211 determines an average value of one of the echo curves corrected by the deviation as an overall average value, that is, an average echo curve can be determined via a plurality of measurements. To determine the population mean, the sample values of the past echo curve are averaged with the sample values of the current echo curve at the same location in each case. The average echo curve is passed to the final processing device 212, and then the final processing device 212 calculates a distance value for the surface of the filled cargo and one of the measured values based on the determined echo value (for example, a fill) Level). For example, the fill level can be the distance of the fill cargo surface 105 from the reference line 106 and can be supplied for further processing at the output 213 of the deviation determination device 107. To determine the distance, the transmission signal 103 and, in particular, the point in time or the transmission point of the transmission signal 103 can be used as a reference signal.

To determine the deviation when the transmitter 302 is deactivated, the calculation of the arithmetic mean of the plurality of sample values determined within the static range II occurs in the deviation providing device 208 for use in determining the deviation.

3 shows a block diagram of a measurement device 109 including a transmission-reception device 102 and a deviation determination device 107, in accordance with an exemplary embodiment of the present invention. Deviation determination The device 107 is implemented in the example of FIG. 3 as a microcontroller μC 107 on which a computer program product is executed. However, the deviation determining means 107 can also be implemented, for example, in the form of an FPGA (Field Programmable Gate Array), a hardware assembly or a microcontroller in combination with one of the hardware assemblies. The component deviation determining means 107 and the transmitting-receiving device 102 of the measuring device 109 can be passed via the interface 108 having the lead 201 to the actuating element 301 and the control lead 202 via which the control signal Tx_On is supplied to a transmitter 302. Establish a connection between them. The interface 108 also has a lead 203 through which the sampled value of the discretized echo curve C determined by the analog/digital converter 303 is replaced via a lead 203, which has been determined by the transmit-receive device 102, in particular by a corresponding receiver The portion and the A/D converter 303 determine. The deviation determining means 107 may have a storage device 304 for storing an echo curve or a deviation curve and, in particular, for storing the determined deviation value.

The deviation determining means 107 makes the determined measured value available for further processing via the output 213 of the deviation determining means 107.

The high frequency (HF) transmission signal generated by transmitter 302 is forwarded via lead 312 to transmission-reception splitter 305 and via its bi-directional input and output 306 to antenna 110 or coupling device 110' (not illustrated in Figure 3). Transmission signals 103 and 103' are transmitted in the direction of the reflective surface or a plurality of reflective surfaces by antenna 110 or coupling device 110', as illustrated in Figures 1 and 1a, respectively. Also received and supplied via antenna 110 or coupling device 110' via transmit-receive splitter 305 (which may be, for example, a circulator device or a directional coupler) at one output 307 of transmit-receive splitter 305 Once the reflected signal is used as an analog echo curve (or analog reflected signal) A. The analog echo curve A is substantially periodic with respect to one of the cycle durations by which the transmission signal 103 is transmitted. The analog echo curve A is supplied to a mixer 308, a correlator 308, or a sampler 308, wherein analog echoes are formed by means of a local oscillator (LO) 309 such that one of the time-spread analog echo curves B is formed. Curve A is sampled. A time-sequence analog echo curve B can be generated using a sequential sampling method. Can be output via the mixer 310 passes the analog to time-expanded analog echo curve B to amplifier 311. The sampler 308, the local oscillator 309, and the amplifier 311 together form one of the cores of the receiver device of the transmission-reception device 102.

By means of the control signal Tx_On, the transmitter 302 is driven or controlled via the signal lead 202 such that the transmission of the transmission signal 103 is prevented for a predefinable static range. The result in the echo curve A is that a periodic echo signal occurs corresponding to the turn-on and turn-off of the transmission signal or a static signal that typically lasts for a plurality of cycle durations t1. As a result of the time spread in the sampler 308, the result is a time-expanded analog echo curve B, whereas in the time-expanded analog echo curve B, the static signal (now due to the time spreading method) only lasts for a cycle of the analog echo curve B. One percentage of duration. This means that a combination curve composed of an echo curve and a deviation curve is provided at the analog/digital converter 303 via the connection 313 as an output of the amplifier device 311. The analog/digital converter 303 can be regarded as a virtual boundary 314 between the analog-side transmission-receiving device 102 and a digital-side-side deviation determining device 107. The analog/digital converter 303 samples the received time-spread analogy reflection curve, digitizes it, and causes a discretized echo curve C to be used via the output lead 203 at the deviation determining device 107. Therefore, the lead 203 of the deviation determining means 107 obtains the time spread sample value of the reflected signal recorded by the transmission-reception device 102.

4 is a schematic representation of one of the various steps of a method for generating a time spread sampled value of a reflected signal in accordance with an embodiment of the present invention by means of a timing diagram. It is illustrated how the received echo curve A can be processed in such a way that it can be used to determine a bias value. Due to the periodic transmission of a pulse shaped transmission signal 103, a corresponding periodic analog reflected signal 400 is produced. The periodicity of the signal occurs as a pre-defined number of reflected signal curves 404a, 404b, 404c received during a measurement range I are joined together. The first cycle duration t1 of the transmission signal 103 thus produces a periodically reflected signal having one of the first cycle durations t1. Downstream of the transmit-receive splitter 305 An analog reflected signal 400 is produced at the location indicated by A in FIG. The analog echo curve A is plotted as a abscissa via a time scale 401. The shape of each of the signal curves 404a, 404b, 404c may be slightly different for each cycle duration t1 due to fluctuations in the interior of a slot 100 or varying fill levels or other effects. However, due to the short duration of a single cycle duration t1 at least over a longer time interval compared to the duration of one of the fill levels, the reflected signal 400 represents a substantially constant echo signal such that At least a periodic signal is discussed during interval I.

By sampling the mixer 308, which operates with a local oscillator 309 for a second cycle duration t2 and sampling the analog signal 400 with this second cycle duration t2, a sample value 409b is exactly generated for the first cycle duration t1. , 409c, 409d, 409e, 409f. Additionally, since the second cycle duration t2 is greater than the cycle duration t1, the sampled signal travels along the reflected signal 400 in a first cycle. There is a sample value 409b for the signal curve 404b, a sample value 409c for the signal curve 404c, a sample value 409d for the signal curve 404d, or an associated sample value for each of the reflection curves typically for the first cycle duration t1, The sample values 409b, 409c, 409d, 409e, 409f have been generated for a full cycle duration t1. The time spread reflected signal 402 or a time extended analog reflection curve B is reconstructed from sample values 409b, 409c, 409d, 409e, 409f having a cycle duration t2. For example, this time spread reflected signal 402 can occur after sampling due to low pass filtering. The reconstructed analog time-expanded reflection curve can be obtained downstream of correlator 308 at the location indicated by the letter B in FIG. The echo curve B is a time-expanded replica or representation of one of the individual cycle durations t1 of the signal curves 404a, 404b, 404c. In Figure 4, an echo curve B is represented in a standard system that represents the time t in milliseconds (e.g., abscissa) or the distance in meters. The ordinate 420 records the amplitude value of the reflected signal 402 in units of "volts", for example, as voltage or electric field strength.

Since the analog echo curve A basically has one periodic signal of the cycle duration t1, and since the curve B that has been generated is extended from the curve A time, the time-expansion analog echo curve B of the analog echo curve A already has one. Periodic shape or progress. In other words, within the periodic shape of the analog echo curve A, a measurement range I can be determined, characterized in that during the measurement range of the curve B by the second cycle duration t2, a different signal curve 404a One of the waveforms, a shape or progression of 404b, 404c is basically represented as a time-expanded analog echo curve B. Due to the periodicity, if the static range II is generated without the aid of the control device 206, the measurement range I itself will be periodically repeated. The echo curve B has a duration or time interval containing the measurement range I and a duration or time interval of the static range II. Figure 4 illustrates only a single cycle of the periodic reflected signal 402 as the signal is cyclically overwritten to enable display on a screen, enabling storage in a storage device or enabling evaluation.

The deviation determining means 107 allows a turn-off signal to be generated at a boundary 405 after the termination of the measurement range I (i.e., after a predefinable number of first cycle durations t1) to turn off the transmission of the periodic transmission. 302. In time spread reflected signal 402, boundary 405 is represented as transform boundary 405'. When the shutdown occurs periodically in an example, the resulting signal consisting of ranges I and II may also be referred to as a periodic signal. Thereafter, the number of cycles to turn off the transmitter 302 depends on the sampling range to be recorded or to be temporarily stored. The sampling range to be recorded depends on the measurement range I and can, for example, be related to the height of the groove.

The static range II of one of the reflected signals may not be substantially received during the generation by interrupting the transmitter 302. The time duration or length of the static range II is determined such that substantially all of the existing echoes have decayed during this time. The duration of the static range II can be selected such that one range of 1 m is recorded, for example. Therefore, the number of cycle durations each having a cycle duration t1 to be awaited for the static range II is determined. When calculating the cycle duration t1 to be waited for, the static range II may be selected as an even multiple of the first cycle duration t1. Static range II with artificial measurement range I The break is actually the content of the periodic analog echo curve A. Therefore, the analog echo curve A can be considered substantially only as the periodicity of the measurement range I. However, sequential sampling is applicable to the entire analog echo curve A, that is, the measurement range I and the static range II.

The signal values received within the static range II and deviating from the normal values are substantially derived from the interference and define an amplitude deviation 406. The amplitude deviation 406 has the effect that the signal value of the time-expanded analog echo curve B deviates from one of the normal values (specifically also in the static range II). In the example of Figure 4, the normal value is assumed to be a normal value 403 or a zero amplitude value. The combined signal consisting of the measurement range I and the static range II can be considered as an signal having a periodic shape or a periodic progression in one example, since the static range II is always interrupted at substantially the same time. Periodic signal. The combined signal of echo curve 407 and deviation curve 408 is also periodic. Static Range II should not cover the entire range of the measurement range that is not the application. With regard to energy consumption, it should be noted that for static range II, only as much time as is necessary is required to have sufficient time to determine the deviation value. The static range II can be selected to be relatively short, for example, corresponding to a distance of 1 m. Between the static range II and the beginning of a new measurement range I, a standby range III will occur, wherein the transmitter 302 of a transmission-receiving device 102 and the receiver portion of a transmission-receiving device and the analog/digital converter 303 can be revoked to save energy. Then, the time extension cycle duration corresponding to the non-time extended cycle duration t1 will be the duration of the range I+II+III.

The echo curve 407 is recorded or temporarily stored in the measurement range I, while the deviation curve 408 representing substantially only the level or value of the amplitude deviation 406 is recorded in the static range II. The time spread analog echo curve B is generated by the mixer 308 from the sampled value of curve A. During this conversion, the sampled value of curve A is converted back to a time-expanded analog echo curve B by means of subsequent low-pass filtering. The analog/digital converter 303 determines the time spread sample values 421b, 421c, 421d, 421e, 421f of the discretized echo curve C, wherein in FIG. 4, the sample values 421b, 421c, 421d, 421e, for simplicity, 421f and sampled value 409b, 409c, 409d, 409e, and 409f are identical. Therefore, in FIG. 4, it is assumed that the duration t2 coincides with t3. In the case where t2 and t3 do not coincide, the sampled values 421b, 421c of the discretized echo curve C are generated by sampling or digitizing the echo curve 407 and/or the deviation curve 408 with a third cycle duration t3. 421d, 421e, 421f. Therefore, the sampled values 421b, 421c, 421d, 421e, and 421f generated by the analog/digital converter form time-expanded sample values 421b, 421c, 421d, 421e, and 421f including reflected signals having a gap of t3 as interpolation points. The discretized echo curve C. The discretized echo curve C of the time spread sample values 421b, 421c, 421d, 421e, 421f of the reflected signal may be supplied to the deviation determining means 107 for further processing.

Figure 4 also illustrates control range 410 by means of dashed lines extending parallel to the abscissa. Control range 410 illustrates one of the tolerance ranges of the deviation. If the deviation is within this tolerance, then a substantially unrestricted effect can be assumed to act on the echo curve. A limiting effect occurs if the amplitude of the echo curve intermittently deviates from the voltage range in which some of the hardware components have their specified operating range. For example, the analog/digital converter 303 can generate valid digital values only for input signals within a certain input voltage range. If the amplitude value of the echo curve is sometimes outside this voltage range, a signal limit for tampering with the echo signal at this time occurs. Therefore, deviation shifting of one of the echo curves that are too severe can easily lead to a signal limitation and must be avoided for this reason. If the determined deviation will be outside the control range, then appropriate action must be taken to correct the situation. This action can be made to one of the hardware components, for example, to one of the settings of the actuating element 301 that can correct the deviation via the amplifier 311.

The time-expanded analog echo curve B and the discretized echo curve C also relate to a periodic signal, wherein over time, a measurement range I or an echo curve 407 and a static range II or a deviation curve 408 Repeatedly string together in an alternating sequence. The boundaries 405', 405 between the measurement range I and the static range II can be varied arbitrarily by deactivating the activation device 214. For example, the deviation determining device 107 can identify the end of the measurement range I, wherein a set slot height h coincides with a corresponding transition time value or a distance value. use The boundary 405 between the measurement range I and the static range II can be set by parameterization (i.e., by parameter setting) by means of a setting device. The measurement range I can be predefined during parameterization. In another example, the boundary can be determined by calculation using the groove height h typed in a deviation determining device 107. For example, this calculation may allow the boundary 405 to be at a distance corresponding to 1.5 times the slot height or a distance corresponding to the slot height plus 3 m.

By means of the proposed method, the deviation of the echo curve can be determined at any time, for example by means of a deactivation device 214 or a control device 206 in the same sampling procedure as the actual measurement signal, ie The cumulative cycle duration period resulting from the cycle duration of the measurement range I and the static range II.

To determine the deviation, the transmitter 302 is deactivated after recording or capturing the echo curve I and another short range is recorded or retrieved for the deviation determination. In one embodiment of the handover, the number of samples or the number of points can be recorded. The sampling of the deviation curve 408 can begin immediately after the number of points corresponding to the measurement range I has been recorded and the transmitter 302 has been deactivated. At least one single sample point of the analog/digital converter 303 will be sufficient for determining the offset value. In order to make the range II still short enough, a plurality of points can also be recorded, for example, up to 200. The 200 sample values of the static range II may correspond to approximately 1 m to 2 m on one of the time scales. Since only a few sample values recorded in this static range II must be stored compared to the storage of a complete curve, the storage requirement for the deviation determination can be only a fraction of the storage area that the full curve will require.

Since the reference signal can be determined (for example by means of the undo start device 214) for the possibility of offset compensation at any time, it can be prevented from being caused by temperature, component aging or other physical variables (EMC) The effect of the possible change or deviation of the reflected signal 402 and the reference signal. The time-spread analog echo curve B can also be described as an IF signal (intermediate frequency signal) because its frequency is lower than the frequency of the originally received reflected signal 400.

Can be substantially excluded by sampling the deviation signal when the transmitter is deactivated The effect of the range II of the deviation correction value is determined, for example, by the influence of a plurality of echoes in the high-narrow groove. It takes a very long time for a plurality of echoes to gradually decrease in a narrow groove. In such slots, if the region is used for deviation determination at the end of the echo curve or at the beginning of the next echo curve, then this determination can be falsified by multiple echoes.

Furthermore, the deviation can be corrected by means of one of the digital corrections in the actuator element 301 and/or the aberration correction device 209. The correction by means of the actuating element 301 first acts on the next discretized echo curve C, which is why the instantaneous curve can still be "affected by the deviation". Therefore, the first correction first has an effect on the discretized echo curve C that is next sampled by the analog/digital converter 303. Due to the continuous determination of the offset value, the software currently in the processor 107 can also be corrected by means of a calculation rule or by digital signal processing (for example, by adding or subtracting a deviation value) to correct the current presence in the echo curve. The deviation on the top. This second correction can occur in the offset correction device 209. Digital signal processing is possible when there is a discretized echo curve C as one of the discrete values that can be accessed by the digital processing system. The actuation component 301 provides a first analog correction on the analog side of the analog/digital converter 303 and the processor 107 provides a second digit correction on the digital side of the analog/digital converter 303. The calculation during digital signal processing can result in a delay in the measurement results.

An echo curve is needed for the determination of the measured value. The recording or sampling of the signal curves 404a, 404b, 404c generated by the transmission-reception device 102 is initiated by a microprocessor [mu]C 107. The activation or control of the transmission-reception device 102, the analog/digital converter (or sampling device) 303, and the actuation element 301 is implemented via this μC 107 for deviation control.

The μC 107 determines the number of sample points recorded. If μC 107 (specifically, control device 206) has recorded the required distance, that is, if a pre-defined number of sample points have been recorded, then the transmitter 302 is deactivated by μC 107 and the deviation signal is sampled immediately. Start. Only the static range II of the analog signal B is sampled for digitization of the deviation range. In one example, 200 sample values are generated. Therefore, the number of sample values to be stored The case is lower than the case where the complete echo curve will be stored within the measurement range. For example, a complete reference curve must be stored. Only one small storage space or low capacity storage device 304 is necessary for 200 points or 200 sample values of the example compared to the sample values generated during digitization of an echo curve.

The deviation magnitude of the echo curve is determined within the deviation determining means 208 by calculating an average (for example, an arithmetic mean) based on the sampled value of the deviation curve.

The actuating element 301, which can influence the static level of the time-expanding analog echo curve B, can be implemented by means of a digital potentiometer. A correction value is passed to the amplifier 311 via the lead 320. The amplifier 311 can be implemented as a differential amplifier. The actuating element 301 can also be implemented as a digital actuating element having a D/A converter (digital/analog converter). The actuation element 301 can directly generate a control voltage and does not require an additional voltage divider. Yet another possibility of implementing the actuating element 301 would be to generate a PWM signal (pulse width modulated signal) that is converted to a DC voltage by means of an RC element. This DC voltage then acts as a control voltage.

If it is not necessary to control or adjust the static level by means of an analog actuating element 301 driven in a digital manner, a voltage divider or potentiometer can also be used to trim the module. However, in this case, the changed bias value will not be automatically reacted. These actuating elements will have to be manually adjusted. As an alternative to partial digital control using a digital potentiometer, it is also conceivable to have a complete analog control system in which a bias voltage is measured in a analogy manner to generate an analog control voltage via an analog amplifier and a controller.

To measure the deviation, the transmission-receiving device 102 is turned off, specifically the transmitter 302 of the transmission-reception device 102 that is responsible for generating the transmission signal 103, and a portion of the transmission-reception device 102 responsible for receiving remains in effect. Transmitter 302 is used to turn off transmission-receiving device 102. Various possible configurations for shutting down the transmitter 302 can be made first. Transmitter 302 has at least one clock oscillator 502 and a pulse generator 501.

FIG. 5 shows the transmitter 302 being turned off by deactivating an oscillator 502 in accordance with an exemplary embodiment of the present invention. In order to accomplish this, the control signal Tx_On is used for transmission. The cycle duration t1 of the signal 103 produces an oscillator 502 of the clock pulse. In this example, lead 202 is coupled to oscillator 502 and the Tx_On signal turns "on" or "off" oscillator 502.

FIG. 6 shows turning off transmitter 302 by revoking startup pulse generator 501, in accordance with an exemplary embodiment of the present invention. Before the signal generated by the oscillator 502 is supplied for transmission to the transmission-reception splitter 305 of the antenna 110, the signal is supplied to the pulse generator 501 as a clock. If the pulse generator 501 is turned off, then any transmitted signals or transmission pulses that are generated will no longer exist.

FIG. 7 shows turning off the transmitter 302 by means of an on/off switching device 700, in accordance with an exemplary embodiment of the present invention. Transmitter 302 has an on/off switching device 700 between pulse generator 501 and transmit-receive splitter 305. The on/off switching device 700 is inserted in the signal path of the transmission pulse. The switching device 700 or the switch 700 is turned on/off via the lead 202 by the control signal Tx_On and turned on or off. With this configuration, the start transmitter 302 can be revoked, wherein the switch 700 opens or closes the connection between the pulse generator 501 and the transmit-receive splitter 305. Transmitter 302 is activated when switch 700 is closed.

It should be noted that the portion of the transmission-reception device 102 responsible for transmission may be partially turned off independently of the transmission-reception device 102 responsible for receiving a signal.

In FIGS. 5, 6, and 7, the transmission-reception device 102 includes an A/D converter 303, and in FIG. 3, the A/D converter 303 is external to the transmission-reception device. Therefore, the A/D converter 303 can be integrated in the transmission-reception device 102 or can be disposed outside the transmission-reception device 102.

Figure 8 shows a flow chart of one of the deviation correction sequences. Thus, Figure 8 shows a flow chart of one of the methods for determining a deviation in accordance with an embodiment of the present invention. The method begins in step S0 and receives a time spread sample value of a reflected signal of one of the transmitted signals in step S1, the signal being held by the transmit-receive device 102 in a first cycle prior to being received Continued time t1 transmission.

In step S2, one of the measurement ranges I of the identification echo curve 407 ends. In addition to the measurement range I of the echo curve 407, that is, after the number of sample values envisaged for the measurement range I has been recorded, a control signal (or turn-off signal) Tx_On is supplied to the transmission-reception device 102, which The signal may at least intermittently revoke the transmission of the initiate transmission signal 103 to produce a predefinable static range II within the time spread sample value of the reflected signal 402. The duration of the supply of the control signal Tx_On may be predefined or may be variably adjusted by means of the control device 206 for the duration of the shutdown signal. The duration of the turn-off may be long enough to ensure that the duration of the static range II continues for a sufficiently long time to sample a sufficient number of sample values. That is, if a lower sampling rate of 1/t3 of the A/D converter 303 is used, the static range II will be longer than the case where a high sampling rate is used so that the same number of sample values can be read.

In other words, in the case of the start of the transmitter 302, the time-spread analog-like echo curve B is digitized by means of an analog/digital converter 303 and converted into a corresponding discretized echo curve C.

If μC 107 has recorded the desired distance for measurement range I, then μC 107 will deactivate start transmitter 302 and sampling of deviation signal 408 will begin immediately. For example, the required distance of range I will be specified based on the number of sampling points. Regarding the sampling of the deviation signal 408, only one of the analog signals will be sampled in the static range II, for example, 200 sample values.

In step S3, it is determined that the value of one of the amplitude deviations 406 in the static range II deviates as one of the normal values 403. With respect to this deviation determination, the echo curve 407 and the deviation curve 408 are determined, for example, by determining the arithmetic mean of a subgroup of samples from the static range II or from all sample values based on the sample value of the deviation curve 408. The magnitude of the deviation of the entire echo curve. Regarding correcting the deviation of the entire echo curve, it is assumed that the same deviation that was determined for the deviation curve 408 was or was valid for the echo curve 407.

In step S4, the self-bias value is supplied before the method has reached the final state S5. Export one of the characteristic quantities or derive one of the signals from it.

9 shows yet another flow chart of a method for determining a deviation in accordance with an embodiment of the present invention.

This additional method begins with a step S6 of indicating an initial state. An echo curve that will be used to determine the measured value (for example, the fill level) is generated in step S7. To generate an echo curve, a pulsed transmission signal 103, 103' is transmitted by antenna 110 or coupling device 110' and a transmission-receiver separator 305 is used to record the echo curve A generated from the pulsed transmission signal. The sampling is initiated by the sampling control device 206 in the deviation determining device 107 that can be implemented as the processor 107 or the microcontroller 107. The sampling control device 206 or control device 206 in the deviation determining device 107 also drives a sampling device that can be implemented as an analog/digital converter 303. By means of the connection leads 201, the deviation providing means 208 controls the actuating element 301 (for example a digit potentiometer) and thus achieves the implementation of a deviation control.

A time spread signal B is formed from the echo curve A by means of the action transmitting-receiving device (or transmitter) 102 by means of the mixer 308. The time-spread analog echo curve B is then transformed by means of an analog/digital converter 303 into a digital representation C, that is, transformed into time-expanded sample values 421b, 421c, 421d, 421e or a discretized echo curve C.

In step S8, the deviation determining means 107 determines whether or not the required distance of the measurement range I has been recorded. Therefore, it is determined whether or not the predefinable number of sample values 421b, 421c, 421d of the discretized echo curve C within the measurement range I are appropriately explained by the deviation determining means 107. If it is determined that the entire measurement range I of interest has been recorded (ie, a complete echo curve 407 or a complete echo curve 407), the transmitter will be deactivated by the control signal Tx_On in the lead 202 in step S8. 302. The result of the undo start is that the transmitted signal transmitted in other manners with the first cycle duration t1 is no longer transmitted, however the receiver portion of the transmit-receive device 102 remains on, with the result being a boundary after a measurement range I A static range II is formed at 405. Only signals that are not attributable to the transmission of a transmission signal 103 are received in this static range II. When the transmission-reception device 102 is turned off The transmitter 302, but the receiver portion of the transmission-reception device 102, functions regardless of the turn-off of the transmitter 302, and only the interference variable or interference effect on the receiver portion of the transmission-reception device 102 is recorded in the static range II. .

In step S9, the sampling of the deviation curve 408 (i.e., the evaluation of the sample values in the static range II) may begin immediately after transitioning to the boundary 405 of the boundary 405' between the echo curve 407 and the deviation curve 408. Therefore, the deviation signal or deviation curve 408 is sampled substantially immediately after the measurement range I. The deviation determining means 107 comprises a deactivation enabling means 214 by which one of the transmission signals 103, 103' can be immediately stopped. The boundaries 405, 405' can be shifted by applying the undo enable device 214.

Only one of the deviations 408 of the reflected signal 402 is sampled for the determination of the offset value. This deviation curve 408 (specifically, the signal value of the time-spread analog echo curve B belonging to the static range II) is sampled with relatively few sample values. Therefore, the portion of the static range II or the static range II used for the determination of the deviation can become relatively small. In the range used for evaluation, by turning off the transmission signal, the existing signal can be reduced to a signal that is substantially responsible for the correct reception of the interference echo curve. Therefore, with respect to determining the offset value, it is not necessary to save or store a complete reference curve for one of the echo signals for an empty slot, for example, one of the entire echo curve 407 of the measurement range I. Sampling is sufficient with relatively few sampling steps. For example, saving 200 samples is sufficient to determine the bias value. Therefore, one of the storage devices (or memory) 304 of the deviation determining device 107 can become smaller.

The magnitude of the average deviation of the echo curve can be determined by determining or calculating the arithmetic mean from the sampled value of the discretized echo curve C belonging to the static range II (i.e., the sampled value from the deviation curve 408). This deviation value can be used in different ways to correct the echo curve. The calculation by means of the averaging deviation is performed in step S10.

In step S11, the correction value determined from the calculated deviation value may be output, for example, via the first output 210a of the deviation providing device 208.

In step S12, the determined correction value or deviation value may be used to follow the deviation The value is corrected by discretizing the echo curve C. This correction of the echo curve according to the deviation can occur on the analog side of the measuring device 109 and/or on the digital side of the measuring device 109, that is, before the analog conversion by means of the A/D converter 303 and/or Or after that.

The lead 201, together with the actuating element 301 and the feedback lead 320 introduced at a second output or a second input of the amplifier 311, can implement a closed loop deviation control, an open loop deviation control or a deviation control loop. The actuating element 301, which is controlled by this deviation, shifts the static level of the analog echo curve B, as a result of which the discretized echo curve C is also shifted. Regarding the determination of the measured value, the static level should substantially correspond to the normal value, because in this case, the detection curve or the threshold curve can be placed very close to the echo curve. The analog echo curve B can be shifted by means of the actuating element 301 as close as possible to a normal value 403 or a zero amplitude value. By approximating the echo curve B to the normal value 403, an analog echo curve B can be supplied at the output of the amplifier 311 for which no offset correction or only a small offset correction coefficient is necessary on the bit side. Furthermore, the echo element B can be prevented from being too far away from its desired static level by means of the actuating element 301, as a result of which a limiting effect can result in a measurement error. If the analog echo curve B is too far away from the desired static level (ie, the normal value 403), the echo curve B can be derived from the input recording range from one of the amplitude values of the analog/digital converter. So trim it. Trimming, trimming, capping or limiting of echo curve B will result in a "rectangular" echo progression and it will no longer be possible to determine exactly the maximum value of an echo. Deviation correction prevents this range from being exceeded.

However, the echo curve determined in the same sampling procedure as the offset value may still contain a small deviation and thus may still be shifted. In other words, although the deviation is corrected on the analog side, there may still be a deviation shift because the determination of a deviation may only have one effect on the subsequent signal. The echo curve determined in the same sampling procedure as the deviation value is recorded in chronological order before the deviation value is determined, and therefore the echo curve has not been affected by the feedback of the deviation correction value via the actuation element.

The following facts are understood by the term "same sampling procedure". If the time-expanded echo signals B and C are each considered to have a measurement range I and a static range II as periodic signals of a combined cycle duration, the term "same combination cycle duration" means All sample values are within the same combined cycle duration of ranges I and II. Thus, the time-spread reflected signal 402 of FIG. 4 exhibits one of the cycle durations from the same duration of the same sampling procedure in which an offset value is also determined, with the cycle duration of the echo curve 407 and the cycle duration of the deviation curve 408. Wave curve. The reflected signal 402 (specifically, the deviation curve 408) used to determine the deviation still contains the deviation. Although this is corrected by hardware for the subsequent curve so that the current curve is almost unbiased, it must still be corrected in a computational manner.

The method finally ends in step S13.

The method described makes it possible to correct the current curve using the deviations that have been determined in the previous steps. The determination of a deviation value has only one effect on the time-expanded echo curve on the analog side. The digital echo curve located in a memory can be corrected by determining one of the deviation values before supplying the measured value. The digital echo curve can be corrected by determining a deviation value after storing one of the digital echo curves in a memory in the memory and before supplying the measured value. By subtracting or adding the offset value based on the sign of the sampled values 421b, 421c, 421d, 421e from the discretized echo curve C, it may be supplied downstream of the deviation correcting device 209 (i.e., after the correction bias) There is basically no deviation from one of the echo curves. By a parallel application of the analogy of the offset correction and the one-bit offset correction, the averaging device 211 and the final processing device 212 can be supplied with an almost non-deviation echo curve for performing the measured value determination. The echo curve that can be used to average device 211 or average device 211 can be made very close to the detection curve due to its substantially unbiased nature, and thus can be determined by final processing device 212 even when using a biased These echoes will no longer be visible or detectable when echoing the curve.

Due to the ability to subsequently correct the discretized echoes in a digital or computational manner The possibility of line C (i.e., processing of the echo curves by means of a microprocessor 107) also prevents the biasing control actuator element 301 from having a very high resolution. In other words, this means that only the accuracy or resolution of the actuating element 301 (for example, the resolution of the digital potentiometer) can be compared to perform an analogy of the deviation. As long as the deviation corresponds exactly to this resolution or a multiple thereof, the deviation can thus be completely corrected or removed. In all other cases, after correction via the actuating element 301, only one of the residual corrections can be calculated or removed. However, in any case the residual deviation can be assessed to be so small that it is within the control range 410 and therefore there is no need to worry about the limiting effect.

Therefore, the feedback of the bias value can be made or progresses smoothly with a low resolution. If the extremely high resolution of the element 301 is inevitably actuated, the resolution of the actuating element will have to be at least half of one of the LSBs (Least Significant Bits) of the A/D converter so that it will no longer be responsive to the echo The curve determines a deviation.

The method and apparatus described can prevent limitations regarding the use of one of the two echo curves. In one aspect, determining one of the ranges of one of the echo curves before a reference pulse and considering the deviation of the two curves when comparing the two echo curves can have one of the two echo curves in the solution The range before the reference pulse for determining the deviation may contain one of the echoes. These echoes can tamper with the deviation determination. On the other hand, in a solution using two echo curves, the effect can also be that individual echo curves are always affected by deviations that can cause a limit on one of the echo curve signals. This deviation is only removed during the comparison of different echo curves.

The method illustrated determines and substantially completely eliminates the deviation of each individual echo curve, and substantially accomplishes the steps set forth below for accomplishing this.

First, a range II of the echo curve is generated which is suitable for determining the deviation, wherein the activation of the transmission pulse is intermittently or temporarily cancelled by means of a signal "TX_On". After the deactivation of the transmission pulse is initiated, the deviation is determined within the range II, 408 mentioned above. Regarding the extensive elimination of the deviation, control occurs via the actuator unit 301. In an example, by The effects of the control are shifted in chronological order for feedback. Control only acts on, for example, the next "shot". Therefore, the control first acts on a second echo curve 407 which follows a first echo curve 407 in chronological order, wherein the deviation correction of the second echo curve is derived from the first echo curve. It can also happen that once one of the deviations has been substantially eliminated before the analog/digital conversion to prevent the limit, a small deviation is maintained. The deviations left after the analog/digital conversion are completely eliminated in the next step. For example, this elimination is performed computationally by subtracting a constant deviation value from all discrete points of the echo curve.

Due to the correction bias, when the transmission-receiving device 102 is turned off, an echo curve is provided which maintains the expected normal value over time curve or over time as all received signals are substantially non-existent ( Or static value, zero value) 403. In the resulting echo curve (i.e., in the echo curve that is passed to the averaging device 211 after correction bias and used for further signal processing), a static value is represented by a known amplitude value that does not exist for all signals. A known amplitude value can be, for example, a value of zero.

By offset correction, each individual echo curve downstream of the deviation correcting device 209 is substantially unbiased, and as a result of this, the reflection or echo can be easily identified even in comparison with a reference curve. Due to the longer range II (determining the deviation during this time interval) compared to the decay duration of the echo in the slot, the determination of the offset cannot be substantially interrupted by the echo. It is possible to prevent, for example, a limiting effect due to deviation. In addition, multi-level deviation cancellation (for example, division into approximate deviation elimination and accurate deviation elimination) can be implemented. Multi-level deviation cancellation provides one combination of analog deviation control and calculated deviation correction. This combination can be cost effective and reduces the cost of implementation for good deviation correction, for example, because components with low resolution can be used.

By means of the deactivation of the activation device 214, the reception static value or deviation curve 408 can be generated at any point in time and at intervals in the echo curve by immediately canceling the activation of the transmission signal (i.e., shortly after the operation of the device is deactivated).

Turn off the transmission signal and generate one of the time extension range corresponding to the static range Used in other applications. In addition to the deviation cancellation described above, the interference echo or spurious echo can be blocked, the reference level can be used to determine the echo amplitude, and the inherent noise of the receiver or the internal noise of the receiver can be determined. The noise level.

Yet another aspect of the invention may be to deactivate a transmitter to obtain a segment having a static level at any point in time within an echo curve. As a result of this, it is possible to avoid having to turn off the receiver and prevent the internal defects of the receiver from generating deviations and noise. The obtained static value can be compared to the known desired static value, and based on the result of the comparison, the deviation due to the internal defect of the received signal can then be calculated. By eliminating the offset, internal defects can be prevented from causing the echo curve signal to be different from the desired static level when the transmitter is deactivated. In this case, the desired static level corresponds to the expected value in the absence of all reflections, which is for a predefined boundary condition.

Transmission, by means of a pulse/transition time measurement without time spread due to "sequential sampling", if all reflections of the last transmission pulse that continues to be turned off or are still propagating are "attenuated", then the transmission is attenuated. The undo start of the signal will only result in a static level. This attenuation can last many times this cycle duration t1 compared to the cycle duration t1 of a single signal curve 404a, 404b, 404c. Expressed as a distance value, the attenuation can be many meters long.

The shutdown transmitter and the use of a combination of one of the time spreading methods by means of cross-correlation or by sequential sampling allow the undo of the transmitted signal to affect the time-expanded echo curve almost instantaneously (by time spreading factor acceleration). With tens of thousands of normal time spread factors, many meters become, for example, only a few millimeters. If the slot height h is 20 m in one example, the reflection is attenuated to a satisfactory measurement sufficient to ensure a static level after only 100 m of a non-time spreading scale. Therefore, the "attenuation range" is 80m. Regarding the one-pulse/transition time method that does not use time expansion, in this example it will be necessary to wait up to 100 m in each transmission/reception cycle before the deviation determination can occur. A pulse/transition time method is used when the combination turns off the transmitter device substantially immediately after the tank height h has been reached With the time spreading technique, the attenuation range is reduced from 80 m to 0.8 mm according to an exemplary time spread factor of 100,000. After the deactivation of the transmitter is initiated, it is therefore only necessary to wait for 0.8 mm until one of the static levels is reliable. In the time spread reflected signal 402, the 1 ms transition time in the timing diagram of the echo curve corresponds to a distance of about 1 m for round-trip propagation or back-and-forth propagation for a local scale. In the non-time-expanded received reflected signal 400 (also referred to as a HF curve), a 1 ms transition time corresponds to a distance of approximately 16,300 m encompassing for round-trip propagation or for back-and-forth propagation. In other words, this may mean that if the reflection is attenuated after the turn-off lasts for 1 ms, it corresponds to a value of 16,300 m in the non-time-expanded pattern and only corresponds to 1 m in the time-expanded pattern.

The present invention can be employed with all pulse/transition time methods using sequential sampling time spreading techniques.

In addition, it should be noted that "comprising" and "having" do not exclude any other elements or steps, and "one" and "a" do not exclude the plural. It should be further noted that features or steps that have been described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference numbers in the scope of the patent application should not be construed as limiting.

107‧‧‧Deviation Judging Device/Microcontroller μC/Microprocessor μC/μC/Processor/Microcontroller

108‧‧‧Interface/standard interface/external interface

201‧‧‧ lead

202‧‧‧ lead

203‧‧‧ lead

204‧‧‧Sampling Receiver Device

205‧‧‧Selector device/segment device/separation device

206‧‧‧Control device/sampling control device/sampling controller

207a‧‧‧ first output

207b‧‧‧second output

208‧‧‧ Deviation providing device

209‧‧‧Error Correction Device

210a‧‧‧ first output

210b‧‧‧second output

211‧‧‧Averaging devices/average devices

212‧‧‧Final processing device

213‧‧‧ Output

214‧‧‧Revocation of the start device

Tx_On‧‧‧ control signal

Claims (15)

A deviation determining device (107) comprising: a sampling receiver device (204) for receiving a reflected signal of one of the transmitted signals transmitted by a transmitter device (302) for a first cycle duration (t1) (C) time spread sample values (421b, 421c, 421d, 421e); a control device (206) for controlling the transmitter device (302); a bias providing device (208); wherein the control device (206) Adapting at least intermittently to provide revocable activation in addition to one of the predefinable measurement ranges (407, I) of one of the time-spread sample values (421b, 421c, 421d, 421e) of a reflected signal (C) One of the transmitter devices (302) turns off the signal (TX_On) to generate a predefinable static range within the time spread sample values (421b, 421c, 421d, 421e) of the reflected signal (C) ( 408, II); wherein the deviation providing device (208) is adapted to determine the reflected signal (C) by evaluating at least one of the time-expanded sample values (421b, 421c, 421d, 421e) The time-expanded sample value (421b, 421c, 421d, 421e) is one of the amplitude deviations (406) from a normal value (403), And the value of the amplitude deviation (406) is supplied at one of the outputs (210a, 210b) of the deviation providing device (208), the sample value being determined within the static range (408, II). The deviation determining device (107) of claim 1, wherein the time interval of the time-expanded sample values (421b, 421c, 421d, 421e) of the reflected signal (C) is a second cycle duration (t2), wherein The second cycle duration (t2) is greater than the first cycle duration (t1). The deviation determining device (107) of claim 1 or 2, wherein the duration of the turn-off signal (TX_On) corresponds to an integer multiple of the first cycle duration (t1). The deviation determining device (107) of claim 1 or 2, wherein the predefinable measurement range (I, 407) is dependent on a slot height (h). The deviation determining device (107) of claim 1 or 2, wherein the time-expanded sample values of the reflected signals are calculated by averaging a plurality of sample values determined in the static range in the deviation providing device (421b , 421c, 421d, 421e) the value of the amplitude deviation (406) from the normal value (403). The deviation determining device (107) of claim 1 or 2, further comprising: a selector device (205); wherein the selector device (205) is adapted to be at a first output (207a) of the one of the selector devices Supplying a time spread sample value (421b, 421c, 421d, 421e) appearing within the measurement range (I, 407), and via the selector device one of the second outputs (207b) will be in the static range (II At least one sample value determined within 408) is supplied to the deviation providing device (208). The deviation determining device (107) of claim 1 or 2, wherein the deviation providing device (208) is adapted to use the value of the time-spread sample value of the reflected signal from a normal value, the reflected signal (B) One of the amplitude deviation correction is performed on the reflected signal before digitization, and/or the value is used, and an amplitude deviation correction is performed on the reflected signal (C) after one of the reflected signals is digitized. The deviation determining device (107) of claim 1 or 2, further comprising: an offset correcting device (209); wherein the offset correcting device (209) is adapted to provide the reflected signal corrected by the value of the offset The time spread samples (421b, 421c, 421d, 421e). The deviation determining device (107) of claim 1 or 2, further comprising: a revocation device (214); wherein the deactivation device (214) is adapted to be at any point in time (for example That is, even within the measurement range (407, I), the turn-off signal (TX_On) is transmitted. The deviation determining device (107) of claim 1 or 2, wherein the time-expanded sample values (421b, 421c, 421d, 421e) of the reflected signal are generated by sequential sampling and/or by digitization. A measuring device (109) having: a transmission-receiving device (102); a deviation determining device (107) according to any one of claims 1 to 10; wherein the control device of the deviation determining device (107) (206) connected to the transmission-reception device (102). The measuring device (109) of claim 11, wherein the measuring device is selected from at least one measuring device consisting of: a quasi-measuring instrument, a limit level measuring instrument, and a momentary A domain reflectometer and a reflectance measuring instrument. A method for determining a deviation of a sample value from a normal value, comprising: receiving a time spread sample value of a reflected signal transmitted by a transmitter device (302) for one of a first cycle duration Providing a turn-off signal at least one of the pre-definable measurement ranges of one of the time-expanded samples of a reflected signal that can be at least intermittently revoked to initiate the transmission of the transmitted signal to produce the reflected signal at the reflected signal Determining a static range between one of the time-expanded sample values; determining one of the time-expanded sample values from a normal value (403) by evaluating at least one of the time-expanded sample values of the reflected signal A value of one of the amplitude deviations (406) that is determined within the static range; the value of the amplitude deviation (406) is provided. A computer readable storage medium having stored thereon a program code, if executed on a processor, the program code instructing the processor to perform the method of claim 13. A computer program product, if the computer program product is executed on a processor, the computer program product instructing the processor to perform the method of claim 13.