Abstract: For reducing speckle in echo signals derived from reflections of pulsed coherent waves, the echo signals are subjected to amplitude and phase/frequency demodulation and the resultant amplitude and phase/frequency data are multiplied to generate an image signal. Selective control of the multiplication process may be provided in accordance with signal amplitude and/or signal-to-noise ratio.

Abstract: A Doppler measuring device for measuring the flow velocity of a fluid which carries particles which reflect ultrasonic waves is described. The device includes an ultrasonic transducer for insonating the fluid with ultrasonic wave pulses in response to corresponding transmit pulses supplied to the transducer at a predetermined pulse repetition rate. A transmitter connected to a transducer and adapted to produce transmission pulses which excite the transducer to deliver the ultrasonic wave pulses is present. The device also includes a receiver connected to the transducer to receive and process echo signals corresponding to at least two groups of echo waves reflected by particles in the fluid, and an evaluator connected to the output of the receiver to derive from the Doppler information obtained by the receiver an output signal corresponding to the flow velocity.

Abstract: A pipetting device comprising a probe for dipping into a reservoir, reaction vessel or the like, a metering pump connected to the probe and a shutoff valve disposed between the probe and the pump are provided. In the intake phase of the pump with the valve open, first air and then a predetermined quantity of liquid is intaken. For at least some of the delivery phase of the pump the valve is in the closed state so that a pressure builds up in the pump. At the end of the delivery phase the valve opens whereby due to the high pressure any adhering liquid particles are expelled.