摘要:
An ultrasonic ground speedometer utilizing Doppler effect comprises an ultrasonic transmitter (2) for outputting an ultrasonic wave at a predetermined angle (ϑ) against a road surface, an ultrasonic receiver (6) for receiving a reflected ultrasonic wave caused by reflection of the output ultrasonic wave from a road surface, an arithmetic circuit (12) for deriving ground speed from Doppler shift between the output ultrasonic wave and the reflected ultrasonic wave. The ultrasonic ground speedometer also includes an output frequency control circuit (13) for controlling the output ultrasonic wave frequency in such a manner as to keep the reflected ultrasonic wave frequency to a constant value in response to changes in ground speed. An amplification degree control circuit (14) also included for controlling the amplitude of the output ultrasonic wave to keep a substantially constant output intensity of the output ultrasonic wave over an output ultrasonic wave frequency range controlled bythe output frequency control circuit.
摘要:
An ultrasonic ground speedometer utilizing Doppler effect comprises an ultrasonic transmitter (1,2,3) for outputting an ultrasonic wave (4) having a particular wavelength (ϑ) at a predetermined angle against a road surface (5), an ultrasonic receiver (6,7,8) for receiving a reflected ultrasonic wave caused by reflection of the output ultrasonic wave from the road surface, and a signal processor (10,11,12) for deriving ground speed from Doppler shift between the output ultrasonic wave and the reflected ultrasonic wave. The particular wavelength is set to a value within a range of 2.6 mm through 3.4 mm to assure the highest possible S/N ratio for the Doppler shift signal obtained from the signal processor.
摘要:
An ultrasonic ground speedometer utilizing Doppler effect comprises an ultrasonic transmitter (1,2,3) for outputting an ultrasonic wave (4) having a particular wavelength (ϑ) at a predetermined angle against a road surface (5), an ultrasonic receiver (6,7,8) for receiving a reflected ultrasonic wave caused by reflection of the output ultrasonic wave from the road surface, and a signal processor (10,11,12) for deriving ground speed from Doppler shift between the output ultrasonic wave and the reflected ultrasonic wave. The particular wavelength is set to a value within a range of 2.6 mm through 3.4 mm to assure the highest possible S/N ratio for the Doppler shift signal obtained from the signal processor.
摘要:
An ultrasonic ground speedometer utilizing Doppler effect comprises an ultrasonic transmitter (2) for outputting an ultrasonic wave at a predetermined angle (ϑ) against a road surface, an ultrasonic receiver (6) for receiving a reflected ultrasonic wave caused by reflection of the output ultrasonic wave from a road surface, an arithmetic circuit (12) for deriving ground speed from Doppler shift between the output ultrasonic wave and the reflected ultrasonic wave. The ultrasonic ground speedometer also includes an output frequency control circuit (13) for controlling the output ultrasonic wave frequency in such a manner as to keep the reflected ultrasonic wave frequency to a constant value in response to changes in ground speed. An amplification degree control circuit (14) also included for controlling the amplitude of the output ultrasonic wave to keep a substantially constant output intensity of the output ultrasonic wave over an output ultrasonic wave frequency range controlled bythe output frequency control circuit.
摘要:
A flow rate sensor is provided. This sensor includes a flow rate detecting element (1). The flow rate detecting element (1) is provided within a flow passage (10) so as to expose the flow rate of a medium whether at the center of the passageway or at the inner surfaces of the passage wall. The flow rate detecting element has a plurality of openings (1a) for allowing the medium to pass therethrough without pressure loss. Thus, the flow rate sensor may precisely detect the flow rate of a medium flowing within the passage regardless of insecurity in the flow distribution of the medium.
摘要:
An ultrasonic vehicle rangefinder having a detecting system for discriminating whether trouble is in transmission or reception side is shown. The discrimination is established by detection of an attenuation vibration at a transmission microphone.