Krautkramer Branson, Inc.

Ulrich Opara

Hanno Jacobs

Franz Selleschy

This invention relates to a method and circuits for the generation and rapid adjustment of direct current voltages, such method and circuits being used particularly for the adjustment of amplifiers, and amplitude and time gates in ultrasonic test instruments. The voltage to be generated is selected by a selector switch and its value is increased or decreased by means of a set switch. For this purpose, the appropriate contents of storage locations of a read-write memory (RAM) are successively read out of the memory for setting the count of a binary counter. The count may be incremented, decremented or left unchanged according to the position of the set switch and of the selector switch. The binary counter contents are then written back into the appropriate storage location of the memory and converted by a digital-to-analog converter (DAC) to an analog value and stored temporarily by means of a capacitor. The individual locations of the memory are successively and cyclically read out so that a continuously recurring sequence is obtained. During each individual cycle the voltage value can be changed by zero or one digital increment. In an alternative embodiment, the repetition frequency is increased by means of a voltage controlled oscillator (VCO) for reducing the time required to complete each individual cycle.

Method and system for generating and adjusting a predetermined quantity

This invention relates to ultrasonic test instruments using wide-band test probes of different nominal frequencies fo and discloses an arrangement wherein each wide-band test probe of different nominal frequency fo is coupled in circuit with a receiving amplifier having a frequency response V(f). The frequency response of the receiving amplifier is so selected that the product H(f) comprising the spectral distribution S(f) of the transmitter and the frequency response V(f) of the receiving amplifier is substantially constant approximately up the the nominal frequency fo of the test probe and has its maximum value in that range. For the transmitters conventionally used in ultrasonic test instruments, in which the transmission pulse is generated by a capacitor discharge, the frequency response V(f) of the receiving amplifier should have a linear rise of 6 dB/octave up to approximately the frequency fo.

Ultrasonic test instrument

An ultrasonic thickness measuring apparatus comprises means for developing pulse counts responsive to the transit time of the ultrasonic search signal traversing the workpiece. The accumulated pulse count is displayed after each transit time interval and is used also to derive a correction factor which is inserted into the counter accumulating the counts during each time interval. This arrangement provides for the apparatus to almost immediately display a thickness value which nearly coincides with the final measurement value.

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Munich, Georgia

Ulrich Opara