Circuit arrangement for the bidirectional operation of a sound transducers disposed at the ends of a measuring section

A circuit arrangement for the bidirectional operation of sound transducers disposed at the ends of a measuring section comprising:

• a signal generator configured as a signal current source;
• a receiver;
• a pair of sound;
• a plurality of switch elements configured to couple one of the pair of sound transducers to the receiver and the other of the pair of sound transducers to the signal generator;
• a terminating impedance connected in parallel with each of the sound transducers, a magnitude of the terminating impedances being greater than an internal impedance of the signal generator;
• and
• a reception multiplexer configured to couple the receiver to at least one of the pair of sound transducers, the reception multiplexer comprising a portion of the plural switching transistors whose control input is supplied by current sources.

A method of determining flow velocity, the method comprising:

• emitting a first sound signal from a first ultrasonic transducer to a second ultrasonic transducer;
• determining a propagation time tdown of the first sound signal;
• emitting a second sound signal from the second ultrasonic transducer to the first ultrasonic transducer;
• determining a propagation time tup of the second sound signal;
• determining the flow velocity along a measuring section based on tdown and tup.