WO1987004799A1 - Appareil de mesure - Google Patents

Appareil de mesure Download PDF

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Publication number
WO1987004799A1
WO1987004799A1 PCT/US1987/000323 US8700323W WO8704799A1 WO 1987004799 A1 WO1987004799 A1 WO 1987004799A1 US 8700323 W US8700323 W US 8700323W WO 8704799 A1 WO8704799 A1 WO 8704799A1
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WO
WIPO (PCT)
Prior art keywords
signals
signal
transmission
transponder
receiving
Prior art date
Application number
PCT/US1987/000323
Other languages
English (en)
Inventor
Eliahu Igal Zeevi
Original Assignee
Eliahu Igal Zeevi
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eliahu Igal Zeevi filed Critical Eliahu Igal Zeevi
Priority to GB8718134A priority Critical patent/GB2203315B/en
Publication of WO1987004799A1 publication Critical patent/WO1987004799A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S7/00—Indicating arrangements; Control arrangements, e.g. balance control
    • H04S7/30—Control circuits for electronic adaptation of the sound field
    • H04S7/302—Electronic adaptation of stereophonic sound system to listener position or orientation
    • H04S7/303—Tracking of listener position or orientation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
    • B25J19/02—Sensing devices
    • B25J19/026—Acoustical sensing devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/87—Combinations of radar systems, e.g. primary radar and secondary radar
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/87—Combinations of sonar systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/87—Combinations of systems using electromagnetic waves other than radio waves

Definitions

  • the present invention relates to measuring apparatus and methods and is applicable to distance measuring apparatus and methods, position location apparatus and methods and to apparatus and methods for adjusting the subjective balance, for a listener, between the channels of a multi-phonic (e.g. stereophonic) sound reproduction facility to maintain the desired audio effect as the listener moves about the room or other space served by the facility.
  • a multi-phonic e.g. stereophonic
  • position location apparatus and methods according to further aspects of the invention may be applied to robotics, e.g. to solve the problem of locating the position of a robot arm in relation to a workpiece or other structural member.
  • One object of the present invention is to provide simple and effective apparatus for measuring distance between two or more fixed or moving points. Another object of the invention is to provide a simple and accurate means for locating the position of an object with respect to reference coordinates, for example the position of a robot arm relative to other mechanical components.
  • measuring apparatus characterized by: at least two transmission devices for transmitting respective first signals; transponder means for receiving said first signals from each said transmission means and for transmitting second signals in response thereto; receiving means for receiving said second signals; and timing means coupled to said transmission means and to said receiving means and arranged to time the time interval between transmission of each first signal by said transmission means and receipt of the corresponding second signal by said receiving means, at least one of said transmission devices and said transponder means being arranged to transmit signals in the form of pressure waves.
  • said first or said second signals are electromagnetic signals, preferably infrared signals.
  • the transponder means is arranged to transmit electromagnetic signals as said second signals.
  • the second signals are preferably of a different frequency from the ultrasonic first signals.
  • the receiving means is positioned at the same location as said transmission means. It is also conceivable however that the receiving means may be positioned elsewhere, for example at a central control unit.
  • the transmission means may include in one embodiment, first and second transmitters at spaced reference locations to transmit respective first signals, and said transponder means may be at an unknown location and responsive to both of the first signals, said timing means being arranged to measure respective timings for said first signals.
  • the transmitters of said transmission means are arranged to transmit at mutually differing frequencies. This permits the individual transmitters to transmit simultaneously without mutual interference.
  • the transmitters of the transmission means are arranged to transmit at mutually differing times. This embodiment enables the first and second transmitters to utilize the same frequency without mutual interference.
  • time division multiplex or frequency division multiplex systems may be employed.
  • said transponder means includes first and second transponders at spaced reference locations which are arranged to transmit respective further signals in response to respective transmissions from said transmission means at an unknown location, said timing means being arranged to measure respective time intervals for said further signals.
  • the transmission means may be arranged to transmit at mutually different frequencies for respective transponders, or may be arranged to transmit at mutually differing times for respective transponders. In either case, interference between the transmissions for respective transponders is avoided in a simple manner.
  • the first and second transponders may be arranged to transmit respective further signals at mutually different frequencies.
  • computing means may be coupled to said timing means.
  • the spaced reference locations my be fixed relative to a pair of loudspeakers, and said computing means may be arranged to further compute a control signal based on said positional data, control means being provided for controlling the power supply to said speakers in response to said control signal in a manner such as to equalise the audio intensity from respective loudspeakers at said unknown location.
  • the reference locations are within respective housings of said loudspeakers.
  • position location apparatus for determining the position of an object characterised by: first and second transmission means at respective spaced reference locations; transponder means on said object for receiving first and second interrogation signals from respective transmission means and for transmitting respective first and second response signals in response thereto; receiving means for receiving said response signals; timing means coupled to said first and second transmission means and to said receiving means and arranged to time a first interval between transmission of said first interrogation signal and receipt of said first response signal and a second time interval between transmission of said second interrogation signal and receipt of said second response signal; and computing means coupled to said timing means and arranged to compute positional data representing the position of said object from said time intervals.
  • the spatial illusion created by stereophonic sound reproduction is, for a given balance setting between the channels, effective only over a relatively small zone within the space served by the system. For example, where the volume settings of two channels of a stereophonic system are equal, the stereophonic effect is obtained only at points equi-distant from the speakers.
  • One object of the present invention is to provide means whereby the above mentioned defects may be avoided.
  • apparatus for maintaining the subjective balance, for a listener, between the channels of a stereophonic sound reproduction facility, or among the channels of a multi-phonic, e.g. quadraphonic, sound reproduction facility, as the listener moves around a space in which the loudspeakers of the facility are disposed, said apparatus being characterised by: a device adapted to be carried by the listener and capable of transmitting signals to receiving means fixed with respect to said speakers, and said receiving means being arranged to determine, from the signals received, the relative distances of the device, and thus of the listener carrying the device, from said loudspeakers and to vary the respective volumes of sound reproduction from said channels accordingly.
  • the receiving means may be arranged to compute the absolute distances of the device from respective loudspeakers.
  • the device adapted to be carried by the listener takes the form of a small unit which may be carried in the listener's pocket or strapped to his wrist after the fashion of a wrist watch, or clipped to his clothing.
  • the device may be arranged, for example, to emit, at short intervals, low-intensity, radio signals which are picked up by receivers mounted close to the respective loudspeakers for the respective channels.
  • a central control facility may then process the signals received by the respective receivers to determine the relative distance from the transmitting device to the two receivers, the control facility being arranged, on this basis, to adjust the balance between the channels to maintain the subjective balance as judged by the listener.
  • the speakers of the two channels may have respective transmitters associated therewith, arranged to transmit signals to the device carried by the listener, and the latter device may be arranged to compare the signals received from the two transmitters and to transmit corresponding data to the central control facility which on this basis determines the position or relative distances of the listener and adjusts the balance accordingly.
  • the ultrasonic frequency may be in the range of 50-100 kHz, although the application is not limited to this particular range.
  • balance adjusting system may be used in conjunction with a system utilizing more than two channels, for example in relation to a quadraphonic system which utilizes four separate channels for sound reproduction.
  • Figure 1 is an explanatory schematic block diagram of ultrasonic measuring apparatus to illustrate the principles of embodiments of the present invention
  • Figure 2a is a block circuit diagram of control and timing apparatus for use in the embodiment of Figure 1;
  • Figure 2b is a functional representation of the circuit of Figure 2a;
  • Figure 2c is a waveform diagram illustrating the principles of operation of the circuit of Figures 2a and 2b;
  • Figure 3a is a block circuit diagram of a transponder for use in the embodiment of Figure 1;
  • Figure 3b is a functional diagram to illustrate the circuit of Figure 3a;
  • Figure 3c is a waveform diagram illustrating the principles of operation of the circuit of Figures 3a and 3b;
  • Figure 4 illustrates a typical radiation pattern of a typical loudspeaker
  • Figure 5a is a block circuit diagram of distance measuring apparatus according to one embodiment of the present invention.
  • Figure 5b shows a reset circuit for use with the embodiment of Figure 5a
  • Figure 6 is a block circuit diagram of a transponder for use with the embodiment of Figure 5a;
  • Figure 7 is a waveform diagram illustrating operation of the circuit of Figure 5a;
  • Figures 8a and 8b illustrate a block circuit diagram of distance measuring apparatus according to a second embodiment of the present invention
  • Figure 9 is a block circuit diagram of a transponder for use with the embodiment of Figures 8a and 8b;
  • Figure 10 illustrates apparatus for stereo balancing according to a further embodiment of the invention
  • Figure 11 illustrates a block circuit diagram of a circuit for use with the apparatus of Figure 10
  • Figure 12 is a block circuit diagram of a further part of the circuit of Figure 11;
  • Figure 13a illustrates characteristic curves of a typical JFET
  • Figure 13b illustrates waveform diagrams illustrating operation of the circuit of Figures 11 and 12;
  • Figure 14a is a resistor arrangement for use with the circuit of Figures 11 and 12;
  • Figure 14b is a circuit arrangement for use with the circuit of Figures 11 and 12 in place of the circuit of Figure 14a;
  • Figure 15 is a schematic diagram of position sensing apparatus according to another embodiment of the present invention.
  • Figure 16 is a block circuit diagram for use with the apparatus of Figure 15;
  • FIG 17 is a block circuit diagram of timing circuitry for use with the circuit of Figure 16;
  • Figure 18 illustrates system scaling apparatus for use with the embodiment of Figure 16
  • Figure 19 is a computing circuit for use with the embodiment of Figure 16;
  • Figure 20 is a further computing circuit for use with the embodiment of Figure 16;
  • Figures 21 and 22 are flow charts illustrating the operation of the circuit of Figure 20;
  • Figure 23 is a waveform diagram relating to the circuit of Figure 16.
  • Figure 24 illustrates application of apparatus according to the invention for ploughing a field
  • Figure 25 schematically illustrates an interrogator provided with a sound-absorbing collar.
  • FIG 1 illustrates schematically ultrasonic measurement apparatus comprising first and second interrogator devices 4 and 5 coupled to a central control unit 3.
  • a transponder unit 6 is positioned at a location spaced from the interrogators 4 and 5.
  • processing circuitry for deriving distance and/or position data from the outputs of respective interrogators 4 and 5.
  • the transponder 6 comprises a receiver and a transmitter and is arranged such as to transmit a signal in response to reception of a transmission from either of interrogators 4 and 5.
  • the measuring process takes place by the transmission of signals from respective interrogators 4 and 5 to the transponder 6 which then operates to send response signals for reception by respective interrogators.
  • the distances from the interrogators may be computed and the position of the transponder relative to the interrogators may if desired be computed from this distance information.
  • the interrogators 4 and 5 preferably each contain a respective ultrasonic transmitter and an infrared receiver, in which case the transponder comprises an infrared transmitter.
  • the interrogator receiver may be an ultrasonic receiver and the transponder transmitter may be an ultrasonic transmitter. Ultrasonic frequencies in the range of 50-100 kHz may be employed although this will depend upon the particular application. To avoid environmental problems, it is preferable that the frequency is above the audible range of any animals likely to be in the vicinity, such as dogs.
  • the transmitters associated with units 4 and 5 have a directional characteristic such that they transmit over a range of angle less than 180 degrees.
  • the transmitter and receiver contained in transponder should be omni-directional.
  • FIG. 2a shows a block schematic diagram of one channel of the processing and control block 3 of Figure 1.
  • a receiver interface 10 receives signals on line 13 from the receiver of interrogator 4 or 5 of Figure 1.
  • a transmitter control block 11 supplies control signals on line 14 to the transmitter of block 4 or 5 of Figure 1.
  • block 11 causes the transmitter to transmit (by producing the control signal) it simultaneously provides a timer start signal on line 16 for starting a timing operation by a timer 12.
  • interface 10 receives a signal on line 13 from the receiver, it emits a timer stopping signal on line 15 for stopping the timing operation of timer 12. The result of the timing operation is then supplied on an output line 17.
  • Figure 2a the circuit of Figure 2a may be considered as shown in Figure 2b which could be implemented as an integrated or hybrid circuit.
  • inputs and outputs RCV2 and TRNSl are provided for the received signal and signal for transmission respectively.
  • Also shown are a reset input, a data output bus and a cyclic signal CYCLE on terminal START which will be explained in more detail hereinafter.
  • Figure 2c illustrates the signal CYCLE together with an indication of the data out information and the timing of the transmitted and received signals.
  • FIG. 3 shows a block schematic diagram of the transponder 6 of Figure 1.
  • a receiver 20 detects receipt of a signal from the transmitter of interrogator 4 or 5 and in response provides a signal to a receiver interface 21.
  • Interface 21 provides a control signal to a transmitter interface 22 which thus causes a signal to be transmitted by a transmitter 23.
  • Figure 3b illustrates a transponder circuit as a functional block.
  • an input signal RECEIVE and an output signal TRANSMIT are shown, the timings of these signals appearing in the waveform diagram shown in Figure 3c.
  • the transponder circuit may be implemented as an integrated or hybrid circuit if desired.
  • FIG. 5a shows a more detailed circuit diagram of interrogator 4 or 5 of Figure 1 and the associated control and processing circuitry.
  • a switch 31 Upon receipt of a cyclic signal START of pulse length DT, a switch 31 closes and allows a sinusoidal signal F]_ to pass from a signal generator 33 via an amplifier 32 to an ultrasonic transmitter 30 as signal TRNS1.
  • the resulting ultrasonic wave is received by the transponder, not illustrated in Figure 5a, which operates to send an infrared signal in response.
  • This signal is detected by a photo-transistor 34 supplied with operating voltage via a load resistor R c .
  • the transistor provides a signal RCV2 to an inverting amplifier 35 whose output STOP is connected to both a delay circuit 36 and to the RESET input of a bistable flip-flop 37 whose SET input is connected to receive signal START.
  • the output of the delay circuit 36 is connected to the clock input of a data latch 38 and to the input of a non-retriggerable monostable multivibrator 39.
  • the output of the signal generator 33 is connected to the non-inverting input of a comparator 40 whose inverting input is grounded.
  • the output of the comparator 40 and of the multivibrator 39 are connected to respective inputs of an AND gate 41 whose output AND is connected to the input of a further non-retriggerable monostable multivibrator 42, the output of which provides the signal START.
  • the Q output of the bistable flip flop 37 is connected to the count input of a counter 43, which is clocked at a frequency F2 and may be cleared by a signal CLR. Data from the counter 43 is read by the data latch 38 in response to the output signal from the delay circuit 36 and is subsequently supplied as output data representing a timed measurement result.
  • the CLR signal is derived from the output of monostable circuit 39 via a differentiator 44, across which a diode is connected.
  • the flip flop 37 is reset so that its output Q stops the counting process of the counter 43.
  • the data latch 38 reads the counter output. The delay is necessary to ensure safe latching of valid data at the counter output. The delay is slightly longer than the time necessary from generation of signal STOP until the counter output is valid. However, the delay is a very short inverval and will be negligible in comparison with the time necessary for sound waves to cover a.practical measuring distance.
  • the output of the AND gate 41 will rise only when the following two conditions are fulfilled: (1) The counter output has already been latched and (2) the output of comparator 40 is high. The comparator output will rise only when the sinusoidal output of the clock generator 33 is rising through zero. This ensures that the output of gate 41 will be true only after the data has been latched and when the sinusoidal output of the generator is greater than zero and rising.
  • the interval timed by monostable circuit 39 should be about 2.5 times the period of the generator 33.
  • the output START of monostable circuit 42 will be high for the transmitting period DT and will be synchronised with the transmitted ultrasound wave. Before the signal START goes high, the counter 43 will be cleared by signal CLR and only after it is cleared will the signal START set the R.S.
  • the flip-flop 37 to initiate counting.
  • the transmitting section is enabled.
  • the generator 33 supplies its output to the transmitter 30 when the switch 31 is closed by the signal- START.
  • the signal START is also available for peripheral circuits wishing to read the data latched in the data latch 38. That is to say, a peripheral circuit may read out the data in response to the START signal. Naturally, in any particular measuring cycle data from the preceding cycle will be read out.
  • switch 31 is closed by signal START for a controlled interval DT to cause a "pulse 11 of ultrasound to be transmitted.
  • the minimum transmitted frequency will be 100X/DT. This must be considered when there is a limit on the frequency which may be transmitted. Generally, the frequency should be maintained as low as possible, because the transmission loss increases as a function of frequency, as will be discussed in more detail hereinafter.
  • Figure 5b shows a circuit for use in conjunction with the circuit of Figure 5a to effect system reset.
  • the output of an OR gate 56 provides a signal for clearing and resetting the counter 43 of Figure 5a.
  • the OR gate 56 has two inputs taken respectively from the output of the debouncing circuit 44 and the output of a similar circuit 55 comprising a capacitor 53, a resistor 54 and a diode 55.
  • the signal input to the capacitor 53 is derived from a monostable circuit 52 which is triggered by operation of a RESET switch 50.
  • the input of the monostable circuit 52 is connected to ground via a resistor 51.
  • FIG. 6 is a more detailed circuit diagram of the transponder 6 of Figure 1.
  • An ultrasound receiver device 60 is connected to an amplifier 61 which in turn is connected to the input of a band-pass filter 62.
  • the output of the filter 62 is connected to the non-inverting input of a comparator 63 whose inverting input is connected to a reference voltage V REF•
  • a non-retriggerable monostable circuit 64 having a period 2 receives its input from the comparator 63 and supplies its output via a buffer amplifier 65 and a differentiator circuit (comprising capacitor 66, resistor 67 and diode 68) to a Schmitt trigger circuit 69.
  • the output of the Schmitt trigger is connected to the base of a first PNP transistor Q ⁇ _ whose collector is connected to base of a second NPN transistor Q2.
  • an infrared transmitter in the form of an LED 74.
  • Resistors 71 and 72 provide correct biassing conditions for the transistor Q ] _.
  • the circuit operates as follows. After filtering by the band-pass filter 62, the received signal is compared with V REF *°y comparator 63 which thus sets the receiver sensitivity. The first rising edge of the received signal at the output of the comparator 63 causes the monostable circuit 64 to be triggered. Further triggering of the circuit 64 is not possible until its time period has expired. The output pulse of the circuit 64 is differentiated by the capacitor-resistor pair 66,67 and any negative pulse resulting is limited to 0.2 volts by the Germanium diode 68. The resulting signal operates the Schmitt trigger 69 which thus operates the infrared transmitter circuit composed of transistors l a d Q2, the LED and the resistors Rj and R2.
  • the pass band of the filter 62 should correspond to the bandwidth DF of the transmitted ultrasound having center frequency F ⁇ _ as discussed above.
  • the detection time of the transponder depends upon V- ⁇ gp at the comparator and may be taken into account when computing the transit time of the ultrasound wave.
  • Waveform I represents the signal at the output of the amplifier 61
  • waveform II represents the output of the comparator 63
  • waveform III represents the output of monostable circuit 64
  • waveform IV represents the output of the capacitor- 66
  • waveform V represents the output of the Schmitt trigger 69
  • waveform VI represents the voltage across the LED 74.
  • DISTANCE MEASURING SECOND EMBODIMENT
  • FIGs 8a and 8b show apparatus generally similar to that illustrated in Figures 5a and 6 but modified to employ ultrasonic transmissions not only from the interrogators but also from the transponder. Thus bidirectional ultrasonic transmissions are employed and infrared transmitters and receivers are not used. It will be appreciated that this "double ultrasound" implementation is fundamentally less accurate than the apparatus discussed with reference to Figures 5a and 6, but may be of advantage in situations where infrared radiation cannot effectively be employed, such as under water.
  • FIG 9 illustrates a transponder circuit for cooperation with the interrogator circuit illustrated in Figures 8a and 8b. Again, components having similar construction and function to those of Figures 5a and 6 are provided with the same reference numerals.
  • Monostable circuit 70 which receives the output of monostable circuit 64 and provides an output to control a change-over switch 31b has no direct equivalent in Figure 5a (although it is analagous to monostable circuit 42) and has therefore been provided with its own reference character.
  • the apparatus illustrated in Figures 8a, 8b and 9 operates with the same ultrasound frequency transmitted from both the transducers and the transponder. If it were desired to employ two different frequencies, two separate ultrasonic transducers could be employed both in the transponder and in the transmitting and receiving circuit.
  • the minimum error will be of the order of one wavelength.
  • a rectifier circuit could be inserted between the amplifier 61 and the filter 62 of Figure 8a. This will permit the comparator 63 to respond at each zero transition of the signal and not only on a positively travelling transition.
  • the frequency of the counter clock should be selected according to the possible accuracy. If measurements are being made to the nearest wavelength and the center frequency of the return wave is F2, the counter clock frequency should be at least F2. On the other hand, if measurements are made to the nearest half wavelength, the clock frequency should be at least 2F 2 .
  • measures must be taken to ensure that reflections of the first transmission are not interpreted by the associated receiver as transmissions from the transponder. This problem can be avoided by using different frequency bands for the two transmissions. Of course, this problem does not exist in the case of the first embodiment, since the interrogator is expecting electromagnetic waves and not ultrasonic waves to be returned.
  • waveforms I, II and III of Figure 7 are also applicable here, where waveform III is the output of monostable circuit 64.
  • This circuit triggers monostable circuit 70 with its positively travelling edge to initiate the transmission interval DT for the transponder.
  • the transmission intervals for the transponder and the interrogation circuit are here considered as the same for simplicity, it will be understood that if desired they may differ.
  • the apparatus includes first and second loudspeakers 100 and 200 coupled to a central control unit 300 of a stereophonic reproduction system having an amplifier 350. Associated with the respective loudspeakers are interrogator devices 400 and 500. The devices 400 and 500 may be located within the respective speaker housings, or may be mounted in separate units attached to respective speakers.
  • a transponder unit 600 is adapted to be carried by a listener and takes the form of a small unit which may be carried in the listener's pocket or strapped to his wrist after the fashion of a wrist watch, or clipped to his clothing.
  • processing circuitry 250 for deriving distance information from the outputs of respective interrogators 400 and 500 to enable the control unit 300 to control the power supplied by the stereo amplifier 350 to respective speakers 100 and 200.
  • the measuring and adjusting process takes place in three stages. First of all, the relative or absolute distances of the unit 600 from the stationary interrogators 400 and 500 is measured, secondly the effect of these distances on the stereo balance is computed, and thirdly the balance is adjusted in accordance with the computed result.
  • the devices 400 and 500 each contain a respective ultrasonic transmitter and preferably also an infrared receiver.
  • the ultrasonic frequencies used are preferably in the range of 50-100 kHz, although the frequency used will depend on the circumstances. To avoid environmental problems, it is preferable that the frequency is above the audible range of any pets likely to be in the vicinity, such as dogs.
  • the system works most effectively when the walls of the room in which it is contained are reasonably non-reflecting. Most domestic living rooms containing curtains, carpets etc. will satisfactorily meet this requirement. This aspect will be discussed in more detail hereinafter.
  • the transmitters associated with units 400 and 500 have a directional characteristic such that they transmit over a range of angle less than 180 degrees.
  • the transmitter and receiver contained in unit 600 should be omni-directional.
  • circuit for the transponder 600 will be constructed in accordance with that illustrated in Figure 6.
  • Blocks 701 and 702 represent infrared receivers, block 810 a timing control unit, and blocks 901 and 902 ultrasonic transmitters.
  • the system operates to send ultrasonic interrogation signals to the transponder by means of the transmitters 901 and 902.
  • a timer of block 810 is started.
  • the timer is stopped, and the timed interval is employed as a measure of the distance to the transponder from the respective interrogator and the associated loudspeaker.
  • circuit 810 is in fact constructed in an analagous manner to that illustrated in Figures 2b and 5a. It will therefore suffice if it is explained that circuit 810 comprises blocks 32, 33, 35, 36, 37, 39, 40, 41, 42, 43, and 44 of Figure 5a so that further description thereof is omitted.
  • a reset arrangement similar to that shown in Figure 5 is provided and includes a monostable circuit 820, a first resistor 821 grounding the input of circuit 820, a capacitor 822, a second resistor 823, and a diode 824. No data latch is provided in the block 810 of Figure 11; this is instead arranged as shown in Figure 12.
  • the apparatus of Figure 11 includes timing logic to ensure correct system sequencing and timing.
  • the object of such timing is to cause interrogation signals to be transmitted alternately from the two transmitters 901 and 902 and to ensure that a response signal is received and processed for each transmission before a further transmission is sent.
  • Such timing is provided by a D-type flip-flop 850 in conjunction with two AND gates 851 and 852.
  • the flip-flop 850 is clocked by the signal START from the processing circuit 810 and provides complementary signals ENl and EN2 on its Q and " Q outputs.
  • the AND gates receive respective signals ENl and EN2 and are also connected to receive the signal START.
  • Output signals from the AND gates are designated LTCHl and LTCH2 and are employed for latching data from the counter of circuit 810 as will be explained with reference to Figure 12.
  • Signals ENl and EN2 are used to control switches SI and S2 for enabling the receiver/transmitter pair 701,901 or 702,902.
  • Figure 13b is a waveform diagram illustrating the signals START (CYCLE), ENl, EN2, LTCHl, and LTCH2.
  • two data latches 812 and 813 receive data from the DATA output of the processing circuit 810 on a data bus 811 in accordance with latching signals LTCHl and LTCH2. This data is then passed through respective digital-to-analogue converters 814 and 815 to provide signals Vg S ⁇ _ and V gs 2 respectively.
  • Vg S ⁇ _ and V gs 2 respectively.
  • the power (in Watts) transmitted from each speaker will have to be changed when the distances d]_ and d2 are changed. Since the power transmitted from the respective loudspeakers is proportional to the square of the voltages (V ⁇ _, V2) applied across respective loudspeaker impedances, and since the power received by a listener falls off as the square of the distance, it may readily be shown that:
  • V ⁇ /V 2 d x /d 2 , where d_ and d2 are distances from the transponder to respective speakers.
  • the balance can be controlled by automatically adjusting the ratio U * 2/U]_ according to changes in the ratio d2/d]_.
  • JFETS active resistances
  • I D drain current
  • V D g drain-source voltage
  • V Q S gate voltage relative to the source
  • operation in the small signal regions of the characteristics can provide controllable resistance.
  • each channel has a series connection of two resistors, R 2' R 1 and R 1' R 2 respectively.
  • the output voltage is taken from the interconnection node of each resistor pair in each case.
  • This sort of arrangement is often used for conventional manual stereophonic balance adjusting, and uses a logarithmic potentiometer, so that linear changes in the balance potentiometer will compensate for the logarithmic sensitivity of our ears.
  • the changes will be linear.
  • FIG. 14b A possible arrangement is shown in Figure 14b.
  • the passive resistors of Figure 14a are replaced by respective JFETs Q ⁇ _, Q2, Q3 and Q4 which are connected in pairs for respective channels and are supplied with current from respective preamplifiers of the amplifier block 350.
  • Vr- is the threshold voltage of each JFET
  • Vg S ⁇ and Vg S 2 are the signals applied to the gates of respective JFETS, it may be shown that:.
  • gate control signals Vg S ⁇ _ and Vg S 2 for the JFETs may be derived as shown in Figure 12.
  • the outputs are taken from the central node of the respective JFET pairs and are connected to respective power amplifiers of block 350.
  • a power compensation circuit could compute a measure of the sound intensity at the position of the transponder 600 caused by the loudspeaker associated with the relevant unit 400 or 500.
  • a similar measurement and computation process could be effected for each loudspeaker 100 and 200 and associated unit 400 and 500. From the resulting information, bearing in mind that received sound intensity falls off as the square of the distance, an appropriate adjustment could be made by a control device contained within the unit 300 to maintain the intensity from each speaker at a constant value as the distance changes. It will be noted that the position of the unit 600 could also be determined from the distance information, since it is located at the intersection of two circular arcs centred at respective units 400 and 500 of radius equal to the computed distances. It is true that this information gives two possible positions for the unit 600, but one of these positions is excluded in the normal case since the loudspeakers are usually mounted adjacent a wall and one of the positions would be outside the room. However, it is not actually necessary to compute the coordinates of the unit 600 in order to correctly adjust the stereo balance or the absolute volume.
  • unit 400 and unit 500 operate in differing frequency bands.
  • the transponder in unit 600 must be capable of receiving and transmitting in two separate frequency bands.
  • signals from units 400 and 500 are time multiplexed under the control of unit 300 and in this case the transponder need only receive and transmit on a single frequency or in a single frequency band. This reduces the complexity of the transponder, but of course correspondingly increases the complexity of the control unit 3.
  • transponder in each of the units 400 and 500 and to replace the transponder in unit 600 by an interrogator.
  • This system would require some means of transmitting data indicating instants of transmission and reception from the unit 600 to the timing unit 250. This could be achieved by means of a wire or by means of a wireless link. However, the added complexity makes this alternative less attractive.
  • Another alternative would be to provide a simple transmitter in unit 600 and receivers in units 4 and 5. Whilst the time of receipt could readily be transmitted to unit 3 in such an embodiment, the difficulty is again presented that a wire or wireless link is required to transmit data indicating the instant of transmission from unit 600 to timing unit 250.
  • units 400 and 500 are built into the housings of respective speakers 100 and 400 all necessary control and data lines may be conducted within a common speaker cable, preferably the same cable utilized for supplying the audio signals to the speaker.
  • Control of the system may be effected either by dedicated electronic control logic circuits as illustrated in conjunction with Figure 5a, or by means of a microprocessor in conjunction with an appropriate program stored in a read only memory.
  • the source (the speaker).
  • the sound power (P) at each point at distance D from the source will be proportional to 1/D 2 .
  • Figure 4 shows a typical radiation pattern of a non-omnidirectional (approx. 180°) speaker.
  • the transmission loss at distance D from each speaker may be regarded as about the same for each speaker because the difference in frequency is usually slight and because there is a logarithmic relationship between the frequency and the transmission loss.
  • the loss characteristic as a function of frequency need not be taken into account.
  • the speaker is a non-isotropic source because it has a non-zero size. This also need not be taken into account because of the following: a) its volume is negligible compared to the volume of the space occupied; and b) in stereophonic systems the supposition is made that all speakers have the same volume, size and structure.
  • the techniques disclosed in this specification may also be applied according to another aspect of the invention to position location for accurately locating the position of an object in two or three dimensions.
  • the position of a robot arm may be determined by using similar techniques as schematically illustrated in Figure 15.
  • a transponder 45 can be carried by a workpiece or other object and can be positionally located relative to respective transmitter/receiver units 41, 42 and 43 fixed relative to the robot.
  • the transponder could be carried by the robot arm itself so that the exact position of the arm relative to transmitter/receiver units fixed relative to a stationary member of the robot may be determined.
  • three pairs of transmitter and receiver e.g. interrogator
  • Each pair will be located at a different point and will interact with the transponder i.e. will transmit signals thereto and receive response signals therefrom. By timing the signal transit times, the distances from respective interrogators may be computed.
  • the distance from each interrogator to the transponder represents the radius of a sphere centered at the interrogator position.
  • three spherical surfaces are defined by the data obtained by the three interrogators.
  • transponder position may be unambiguously determined.
  • transponder is not on the arm, its position with reference to the robot arm will be continually known to the robot processing units because of the following:
  • the distance from each point of the robot body to each of the three interrogator locations will be known to the robot processing units. These three interrogators can in this embodiment be considered as an integral part of the robot body.
  • the transponder will preferably not be located on the object, but rather it will be located at a fixed location with reference to the object.
  • the object position with reference to the robot arm will thus be continually known to the robot processing units.
  • Figure 15 schematically represents a production room for assembly of an electrical circuit board, or for producing some mechanical structure, such as an automobile.
  • the three interrogators 41, 42 and 43 are here located for example in three different wall/ceiling corners, where they would have "line-of-sight vision" of the transponder. They are electrically connected to a control and processing circuit which will be described with reference to Figure 16.
  • the transponder 45 will be fixed with reference to the object to be located (which may be a workpiece or the robot arm) .
  • one timing processing unit When there is more than one production line in the production room, one timing processing unit will alternate between the lines.
  • two separate systems could transmit in two different frequency bands, and two sets of interrogators with associated timing circuitry could be employed.
  • Figures 16, 17, 18, 19 and 20 illustrate details of a hardware implementation for the system illustrated schematically in Figure 15.
  • Figure 16 shows a time measuring system 51 for three distance measuring channels and one scaling channel.
  • the construction of system will be substantially identical to the construction of block 810 of Figure 11, except of course that two additional channels are provided. It is therefore believed that detailed description of block 51 is unnecessary.
  • the output from the timer 51 is supplied to a distance computing circuit 52 which is arranged to compute the distance of the relevant interrogator from the transponder as will be explained in more detail hereinafter. This process is effected for each channel and results in three signals X, Y and Z representing the coordinates in three dimensions of the object. These coordinate signals may be supplied to the processing circuitry of the robot.
  • the computing circuit is controlled by a control circuit 63 which also controls the timing of the time measuring system 51 and the transmit and receive timing. Details of the interrogators 41 to 43 and transponder 45 are similar to the details of the interrogator and transponder already discussed with reference to Figures 5a and 6, so that further discussion is omitted in the interests of brevity.
  • Figure 17 illustrates details of the control unit 63 of Figure 16. As shown, it comprises three D-type flip-flops 631, 632 and 633 in addition to three AND gates 634, 635 and 636.
  • the flip-flops each receive the START (CYCLE) signal on respective clock inputs CLK and receive a reset signal REST on their respective clear inputs.
  • the respective Q outputs of the flip-flops are connected to respective AND gates 634, 635 and 636 and carry signals ENl, EN2 and EN3 respectively.
  • the signal START (CYCLE) is applied to a further input of each AND gate and the outputs of the AND gates provide respective signals LTCHl, LTCH2 and LTCH3. The timings of these signals are illustrated clearly in Figure 23.
  • the time measuring block 51 is connected by lines TRNSl and RCV2 to the respective transmitters and receivers of the three interrogators via the switches Si to S3 so that operation of the switches by means of the signals ENl to EN3 connects the timer to the correct interrogator in each cycle.
  • the reset circuit ensures that the timing and measurement operations are properly coordinated so that the data will be related to the signals LTCHl to LTCH3 in such manner that the data latched with signal LTCHl will be the correct data for distance Ll, and similarly the remaining signals and data are correctly associated with the distances L2 and L3.
  • the reset circuit also is preferably arranged to cause the scaling function to be operated once upon initialisation.
  • the three main interrogators are disconnected from the timing circuit, whilst the fourth interrogator is connected. This condition remains until completion of scaling, i,e. until the scaling data has been latched.
  • the system measures times for the three distances in the following sequence: Ll, L2, L3, Ll, etc.
  • FIG. 18 illustrates a further part of the control unit 63 for controlling the timing of the scaling interrogator 44 which cooperates with a scaling transponder 45a at a known distance from interrogator 44.
  • a D-type flip-flop 640 receives an initial reset signal RES at its clock input and provides the signal REST at its Q output (cf. Figure 17) which is supplied to one input of an AND gate 641.
  • the output of the AND gate 641 supplies a signal LTCH4 to the computing unit 52 as shown in Figure 16 and also to the clock input CLK of a counter 642 which is arranged to produce a carry output at a count of two.
  • the carry output of the counter 642 is effective to clear the flip-flop 640 at its CLR input and is supplied via an amplifier 643 and a capacitor 644 to the clear input CLR of the counter 642.
  • the output electrode of the capacitor is connected to ground through a resistor 645 and a diode 646.
  • the computing unit 52 may be implemented in various ways, and two methods will be described here. A hardware implementation will be described with reference to Figure 19 and a software implementation will be explained with reference to Figures 20, 21 and 22.
  • unit 52 comprises three functional blocks: a scale factor computing circuit 521, a distance computing circuit 522 and a position computing circuit 523.
  • the circuit 521 is connected to receive timing data on line 524 and the signal LTCH4 from AND gate 641 as explained with reference to Figure 18. From the known distance between the scaling interrogator 44 and the scaling transponder 45a, the circuit 521 computes from the timing data a scaling factor V which is in effect a measure of the local velocity of the ultrasound being employed. Data representing this factor is supplied to the distance computing circuit 522, which also receives data representing the timed intervals for each of the interrogators 41, 42 and 43 from the timer 51 and receives the system timing signal CYCLE for synchronisation purposes.
  • Circuit 522 supplies distance information for each of the interrogators in turn to the positioning circuit 523 on line 525 in synchronism with respective latching signals LTCHl, LTCH2 and LTCH3. Having received data for three distances, the circuit 523 computes the position of the transponder from this data and supplies signals X, Y and Z representing the coordinates of the transponder 45.
  • the computation methods for the distance computing circuit 522, the scaling circuit 521 and the position computing circuit 523 present no particular difficulty and will be clear to those skilled in the art, since the computation of various mathematical functions using logic circuits is a well-known technique. Further detail of the computation process will therefore be omitted to avoid obscuring the main principles here disclosed. The mathematics of the position computation will however be discussed hereinafter.
  • FIG. 20 shows a microcomputer 530 for carrying out the functions required for the computing unit 52 of Figure 16.
  • the computer will comprise a microprocessor, a ROM for storing an operating program, a RAM for working storage and an input/output circuit for interfacing the microprocessor with the timer 51, the control unit 63 and any peripheral apparatus such as a robot controller.
  • Any suitable microprocessor may of course be used, but it is suggested that the INTEL 80286 sixteen bit processor would be appropriate.
  • the computer 530 is supplied with an 8 MHz clock signal on line 531 and with data defining the maximum possible values X and Y of the x and y coordinates of the transponder (a maximum value Z for the z coordinate may also be supplied if desired but is not necessary in this implementation) .
  • data line 524, the CYCLE signal and timing signals LTCHl, LTCH2, LTCH3 and LTCH4 are supplied to the computer.
  • Figure 21 shows the main routine stored in the ROM of the computer 530.
  • the processor initialises itself (step 541) and then performs the scaling function on the basis of the scaling data derived from the scaling interrogator 44 (step 542).
  • the processor On the basis of the computed scale factor and the time data generated by the timer circuit 51, the processor then computes the coordinates (x,y,z) of the transponder 45 in step 543.
  • the routine then advances to a decision step 544 and awaits an interrupt. Upon the receipt of an interrupt, the routine returns to step 543 and computes the coordinates again on the basis of the next set of timer data.
  • Figure 22 illustrates the step 543 of Figure 21 in more detail.
  • the program Upon receipt of an interrupt signal (CYCLE) at step 550, the program advances to an initialisation step 551 and then initiates a data reading step 552 in which timer data is read from the timer 51 into predetermined storage locations in RAM. Having collected the data for each interrogator, the processor next performs a distance computation step 553 to determine the distances L ⁇ _, L2 and L3 from the respective interrogation devices to the transponder. When the distances have been computed, steps 554, 555 and 556 are performed to compute the respective position coordinates of the transponder. The processor then returns to the main routine.
  • CYCLE interrupt signal
  • the transponder 45 is located at position (x,y,z) in a system of Cartesian coordinates having its origin at one corner of a parallelepipedal space in which the transponder is located.
  • the three interrogators 41, 42 and 43 are positioned at corners of the space at distances Ll, L2 and L3 from respective interrogators 41,42 and 43. If the coordinates of the corner of the space diametrically opposite the origin are (X,Y,Z), interrogator 41 is at position (0,Y,0), interrogator 42 is at the origin (0,0,0), and interrogator 43 is at position (X,0,0). It will be understood that the following relationships apply:
  • the preferred implementation for the position computation will be by means of the arrangement described with reference to Figure 20 using an INTEL 16 bit processor 80286.
  • a 32 bit processor such as the INTEL 80386 would operate four times faster if required for any particular application.
  • the approximate computing times for addition and subtraction would be 0.5 microseconds
  • the approximate times for multiplication and division would be about 7 microseconds
  • the operation of taking a square root would occupy about 50 microseconds.
  • the square root operation can be performed either by means of a polynomial approximation or, if this is inappropriate for a particular application, by use of a co-processor such as the INTEL 80287.
  • the total computing time required is therefore (roughly) 144 microseconds.
  • the time available for the computation it is necessary to consider both the speed of the transponder (if it is moving) and the minimum transit time for the pressure waves. If the assumption is made that the transponder speed will be small compared with the speed of the waves, the possible motion of the transponder may be disregarded. If the minimum measurement distance is taken as one meter, and the speed of the waves is taken as 350 meters per second, the minimum transit time is 2800 microseconds, which is roughly twenty times the required computation time. It will therefore be apparent that a 16 bit processor is quite adequate for the purpose, and that much shorter distances may be measured and/or the accuracy of measurement may be considerably better than that assumed in the above.
  • FIG. 24 illustrates schematically how this could be achieved.
  • a transponder By placing a transponder on the plough and positioning three interrogators TR]_, R2 and TR3 at corners of the field, the position of the plough may be accurately determined and therefore controlled. (Only two interrogators will be required to determine the position; the third may be used for scaling or omitted since extreme accuracy is not essential in this application) .
  • a further possible application would be for locating the submerged position of an underwater object, such as a remotely controlled submarine craft.
  • a craft may be equipped with surveying equipment for surveying the sea bed, and the present invention could be employed to track the position of the craft and to ensure that it followed a predetermined course or search pattern.
  • the transponder would be carried by the submerged craft and the three interrogators would be placed at various known locations which could be on the surface of the sea or submerged.
  • the invention is applied to use under water, naturally account must be taken of the fact that the velocity of pressure waves is different in water from that in air. Also, it will be apparent that infrared signals would not be practical in this application, so that bidirectional ultrasonics would be employed.
  • Three interrogators may be provided for generating distance information in order to find th.e object position, and according to the distances from the other two moving objects, the object position can be changed. It would of course be possible to measure also the angle to the other moving objects by different methods
  • the accuracy that can be obtained depends upon the wavelength of the ultrasonic waves used, especially when embodiments employing bidirectional ultrasonic transmission are employed.
  • the wavelength is of course equal to the velocity of the waves divided by their frequency. The velocity changes according to the environment and depends upon the mass density of the medium carrying the waves.
  • the maximum accuracy which can be achieved is of the order of half the wavelength.
  • a frequency of 40 kHz will give an accuracy of about 4.15 mm
  • a frequency of 60 kHz will give an accuracy of about 2.77 mm
  • a frequency of 100 kHz will give an accuracy of about 1.69 mm, etc.
  • the receiving circuit in the interrogator takes a finite time DTi to respond following reception.
  • the transponder takes a finite time DT2 to respond following reception of a signal.
  • Problem A can be solved by detecting a predetermined point, such as a rising zero transition, of the sinusoidal signal for driving the transmitter and ensuring that the transmission starts at this fixed point of the sinusoidal signal.
  • the error can be reduced to negligible proportions by use of suitable circuitry, such as that disclosed in this specification.
  • suitable circuitry such as that disclosed in this specification.
  • the errors -rDT ] _ and +DT2 can always be taken into account because they will be exactly known in advance.
  • Problem D can be reduced by half by sensing the rising and falling edges of the transmitted wave so that the total loss of accuracy is no more than about half a wave period.
  • the factor +L/2V is negligible compared with +DT]_ and +DT2, so that the total error will about (+DT ⁇ _) + ( +DT2) to a first approximation.
  • this error will be quite acceptable and in fact the accuracy in this method is virtually dependent solely on the accuracy of the timing technique used to time the transit time. In practice, this means that the accuracy is dependent upon the frequency of a clock generator employed to drive a counter for timing the transit time, the possible error being positive or negative. it is unnecessary to take account of the transit time for the electromagnetic wave because its velocity is greater than that of the ultrasonic wave by a factor of about 10 ⁇ . Thus, accuracy may be improved, if necessary, simply by increasing the clock frequency.
  • the factors *DT ⁇ _ and +D 2 are negligible compared with +L/2V, so that the total error is approximately +L/2V and may be reduced by increasing the frequency of the response wave. Unfortunately, this will also increase the transmission loss since this is proportional to the logarithm of the frequency. Therefore, in any particular case, the frequency of the response wave will have to be selected in accordance with these conflicting requirements.
  • Reflections of the ultra-sound waves from surrounding objects have to be considered. It has already been mentioned in connection with the multi-phonic balancer that the reflections effect must be taken into account for the audio signal, that we can control the volume according to the distance changes bearing in mind that the intensity P varies in proportion to 1/D 2 , that for this purpose we will have to create a medium whose behaviour would be uniform, such as isotropic medium, and that the way to achieve this would be to carpet the room very well, to use an acoustic ceiling and to put curtains on the walls all around, so that in this way the reflections would be negligible.
  • the reflections as a result of the ultrasonic waves will have to be reduced to a minimum in order to avoid incorrect measurement results.
  • the crucial measurement time is the interval from the actual arrival time of the wave at the transponder until a few (about 4) wave periods have elapsed. This is because by that time no direct receiving for this measurement by the transponder would be possible, so that any signals that are received may be attributed to reflections. in fact, the transponder will recognize the received frequency from the first wave to arrive. This will be discussed in more detail hereinafter.
  • any reflections as a result of the first transmission will normally be negligible, and this is why the same frequency may be used for both transmissions.
  • the reflections of the first transmission would die out fast, we still have to try to create an isotropic medium. (In this way we will have less noise and more reliability and the system can be faster).
  • the most important time to avoid reflections would be the time of the first few waves because this is the critical interval during which detection occurs, and this will function more reliably without interference from reflections.
  • the wave length is about 0.35 mm. Therefore, a distance of 1.75 mm, or about 2 mm, corresponds to five wavelengths.
  • An non-reflecting area of at least 2 mm width should therefore be provided around each transmitter.
  • a surrounding area of about 1 cm width may as well be provided since it does not require much extra effort or expense.
  • the wavelength when the frequency is 100 (kHz), the wavelength will be about 3.5 mm and five wavelengths represents a distance of about 1.75 cm.
  • the transponder is arranged to respond with an electromagnetic wave, e.g. an infrared wave, instead of an ultrasonic wave.
  • an electromagnetic wave e.g. an infrared wave
  • the transmission loss for ultra-sound wave is given by the following relationship:
  • TL (dB) 01ogF + 201ogD • *• ,
  • TL is the transmission loss
  • F is the frequency
  • D is the distance travelled
  • K is a constant depending on the specific surface density of the environment.
  • Various types of ultrasonic transducers are commercially available, such as those available from International Specialists Inc and referred to as the Pulse Transit (PT) type which includes a transmitter and a receiver and can operate over a frequency range of from 20kHz to 60kHz. Transducers with various case diameters, e.g. from 12 mm to 24 mm, may be obtained.
  • PT Pulse Transit
  • the number of frequency bands will have to at least equal the number of transponders. It is also possible to operate in parallel during the measuring intervals. For example, three different signals in differing bands could be transmitted simultaneously to a single transponder, if the transponder were constructed to receive and transmit in the three bands.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Electromagnetism (AREA)
  • Signal Processing (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

Un appareil de mesure ultrasonique comprend un dispositif d'interrogation (4, 5) pour transmettre un premier signal ultrasonique; un répondeur (6) pour recevoir ledit signal dudit dispositif d'interrogation et pour transmettre en réponse un autre signal; un récepteur, faisant de préférence partie dudit dispositif d'interrogation (4, 5), pour recevoir ledit autre signal; et un chronomètre (3) couplé audit dispositif d'interrogation pour chronométrer le temps écoulé entre la transmission dudit premier signal par ledit dispositif d'interrogation et la réception du deuxième signal par le récepteur. D'autres modes de réalisation comprennent des émetteurs et des récepteurs pour mesurer les distances et la position à l'aide d'un répondeur. L'invention peut s'appliquer pour ajuster l'équilibre stéréophonique d'un système stéréo de reproduction selon la position de l'auditeur et maintenir ainsi l'effet stéréo, et pour positionner des systèmes de localisation utilisés en robotique.
PCT/US1987/000323 1986-02-11 1987-02-11 Appareil de mesure WO1987004799A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8718134A GB2203315B (en) 1986-02-11 1987-07-31 Multi-phonic balancer

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB868603289A GB8603289D0 (en) 1986-02-11 1986-02-11 Distance measuring apparatus
GB8603289 1986-02-11

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Publication Number Publication Date
WO1987004799A1 true WO1987004799A1 (fr) 1987-08-13

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AU (1) AU7084687A (fr)
GB (2) GB8603289D0 (fr)
WO (1) WO1987004799A1 (fr)

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GB2203315B (en) * 1986-02-11 1991-01-02 Eliahu Igal Zeevi Multi-phonic balancer
AT409421B (de) * 1999-02-23 2002-08-26 Wolf Systembau Gmbh & Co Kg Verfahren und vorrichtung zum trocknen von feuchtigkeit enthaltenden produkten
US8031891B2 (en) * 2005-06-30 2011-10-04 Microsoft Corporation Dynamic media rendering

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DE4027338C2 (de) * 1990-08-29 1996-10-17 Drescher Ruediger Balanceregelung für Stereoanlagen mit wenigstens zwei Lautsprechern
DE4307490A1 (de) * 1993-03-10 1994-09-15 Joerg Cohausz Stereophone oder quadrophonische Anlage
US6799141B1 (en) 1999-06-09 2004-09-28 Beamcontrol Aps Method for determining the channel gain between emitters and receivers
SE518418C2 (sv) * 2000-12-28 2002-10-08 Ericsson Telefon Ab L M Ljudbaserad närhetsdetektor
US20030119523A1 (en) * 2001-12-20 2003-06-26 Willem Bulthuis Peer-based location determination
KR20060131827A (ko) * 2004-01-29 2006-12-20 코닌클리케 필립스 일렉트로닉스 엔.브이. 오디오／비디오 시스템
EP2136577A1 (fr) * 2008-06-17 2009-12-23 Nxp B.V. Appareil de suivi des mouvements

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US3905007A (en) * 1962-03-27 1975-09-09 Us Navy Equipment for locating and plotting the position of underwater towed vehicles
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AT409421B (de) * 1999-02-23 2002-08-26 Wolf Systembau Gmbh & Co Kg Verfahren und vorrichtung zum trocknen von feuchtigkeit enthaltenden produkten
US8031891B2 (en) * 2005-06-30 2011-10-04 Microsoft Corporation Dynamic media rendering

Also Published As

Publication number Publication date
GB8718134D0 (en) 1987-09-09
GB8603289D0 (en) 1986-03-19
GB2203315B (en) 1991-01-02
GB2203315A (en) 1988-10-12
AU7084687A (en) 1987-08-25

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