Krautkramer Branson, Inc.

Krautkrämer Gmbh & Co.

Klaus Volkmann

Benedikt Pollock

Rolf Diederichs

Heiko Bonenkamp

Horst Pollok

Gerd Knapp

Manfred Kickartz

Measuring procedure for the thickness of the mucous membrane of an

An ultrasonic measuring device that is especially suited to nondestructive testing of materials is fitted with an ultrasound test head 72, a transmitter (74) and a receiver (76) that is characterized by a broadband logarithmic amplifier (78). This amplifier consists of several amplifier stages that are identical in construction and connected in series. Each amplification stage is characterized by the fact that it contains two transistorized individual amplifiers, namely a first and a second differential amplifier that are connected to one another and whose transistors (20, 22; 24, 26) are each interconnected at their base and at their collector. Each of these transmitters is connected at the emitters via inverse feedback resistors (34, 36; 40, 42) to a constant-current source (46, 50). At least the constant-current source 46 of one of the two differential amplifiers of an amplification stage is connected on one side to a digital analog transformer (58) that provides corrections for calibrating each connected constant-current source (46).

Ultrasonic measuring device, especially suited to non-destructive

An ultrasonic thickness gauge circuit includes a dual transducer probe and a logic circuit for providing square wave signals whose duration is equal to the time interval between the ultrasonic signal entering a workpiece to be measured and the reception of the ultrasonic signal reflected at the rear surface of the workpiece. When measuring thin wall thicknesses a measuring error arises due to the 'V'-shaped transit path of the ultrasonic signals being greater than twice the wall thickness of the workpiece. A low-pass filter and a comparator are provided for modifying the square wave signals to effect correction. The modified signal is then used for providing clock pulses, the quantity of which is a measure of the wall thickness of the workpiece.

Ultrasonic thickness gauge circuit with transit path correction

A resonant sensing device for measuring the hardness of a workpiece to be tested includes a diamond tipped rod adapted to be resonant and for determining the hardness of a workpiece to be tested is brought into forced contact with such workpiece. The difference in resonant frequency of the rod between its not-constrained condition and its constrained condition (forced contact) is a measure of the hardness of the workpiece. The present invention describes a circuit wherein during a first time interval an up/down counter accumulates the counts arising from the oscillations of the not-constrained rod. During the ensuing interval of the same duration, the counter counts down the accumulated count responsive to the oscillations of the constrained rod. As the counter reaches the zero count condition, which condition is reached before the expiration of the time interval, the counter becomes coupled to an adjustable frequency calibration oscillator and for the remainder of the interval the counter accumulates counts from the oscillations of the calibration oscillator. At the end of the interval, the accumulated count is a measure of the hardness of the workpiece.

Method and apparatus for resonant sensing device

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Bergisch-Gladbach, Germany

Klaus Volkmann