Process for setting the transmission frequency of a distance measuring instrument operating according to the echo-sounding principle
First Claim
1. A process for determining and setting an optimum transmission frequency of a distance measuring instrument operating according to an echo-sounding principle, including at least one electro-acoustic transducer for emitting sonic or ultrasonic pulses and for converting received sonic or ultrasonic signals into electric received signals, a frequency-adjustable oscillator for generating an electric signal having a frequency corresponding to the transmission frequency of the sonic or ultrasonic pulses which are to be transmitted for activating the electro-acoustic transducer, and an evaluation circuit for determining the travelling time of the sonic or ultrasonic pulses as a measure of the distance of a target object, the process for determining and setting the optimum transmission frequency comprising the steps of generating an amplitude-time-profile of the received signals during each of a plurality of reception intervals following the emission of a sonic or ultrasonic pulse, integrating each amplitude-time-profile to produce a plurality of integrated values for different transmission frequencies, storing the integrated values, and tuning the transmission frequency to a selected frequency corresponding to a maximum integrated value.
1 Assignment
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Accused Products
Abstract
In order to set a range finding instrument operating according to the echo-sounding principle using sonic or ultrasonic pulses to an optimum transmission frequency, the transmission frequency is altered stepwise within a predetermined frequency range. During each reception spell following on the transmission of a sonic or ultrasonic pulse an amplitude-time-profile of the received signals is formed and integrated. The integration values obtained for the various transmission frequencies are stored, and an optimum transmission frequency is set to that frequency at which the maximum integrated value is obtained. In order to eliminate the effects of background noise on the determination of the optimum transmission frequency a mean noise amplitude of the received signals is determined and subtracted from the amplitude-time-profile of the received signals before integration.
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Citations
25 Claims
- 1. A process for determining and setting an optimum transmission frequency of a distance measuring instrument operating according to an echo-sounding principle, including at least one electro-acoustic transducer for emitting sonic or ultrasonic pulses and for converting received sonic or ultrasonic signals into electric received signals, a frequency-adjustable oscillator for generating an electric signal having a frequency corresponding to the transmission frequency of the sonic or ultrasonic pulses which are to be transmitted for activating the electro-acoustic transducer, and an evaluation circuit for determining the travelling time of the sonic or ultrasonic pulses as a measure of the distance of a target object, the process for determining and setting the optimum transmission frequency comprising the steps of generating an amplitude-time-profile of the received signals during each of a plurality of reception intervals following the emission of a sonic or ultrasonic pulse, integrating each amplitude-time-profile to produce a plurality of integrated values for different transmission frequencies, storing the integrated values, and tuning the transmission frequency to a selected frequency corresponding to a maximum integrated value.
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25. A process for determining and setting an optimum transmission frequency of a distance measuring instrument operating according to an echo-sounding principle, including an electro-acoustic transducer for emitting sonic or ultrasonic pulses and for converting received sonic or ultrasonic signals into electric received signals, a frequency-adjustable oscillator for generating an electric signal for activating the electro-acoustic transducer, the oscillator signal having a frequency proportional to the transmission frequency of the sonic or ultrasonic pulses emitted by the transmitter, the process comprising the steps of:
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generating an amplitude-time-profile of the received signals during each of a plurality of reception intervals; integrating each amplitude-time-profile to produce a plurality of integrated values corresponding to different transmission frequencies; selecting a maximum integrated value from the plurality of integrated values; and adjusting the frequency of the oscillator to a frequency corresponding to the selected maximum integrated value.
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Specification