U.S. Philips Corporation

Theodorus J Van Kessel

Eise Carel Dijkmans

Abraham Hoogendoorn

By Friedrich De Haan, Administrator

Nico V Franssen, Deceased

Albertus J Van Uden

Hendrikus Fransiscus Bloemen

Eric Henricus Stulemeijer

Johannes Maria Pieper

Robert Emile Van De Grift

By adding the difference between output and input of the one amplifier section to the output signal by means of a subsequent amplifier section a ring of amplifier sections can be formed which compensate for each other's distortion.

Amplifier arrangement with parallel-operated amplifier sections

A step-controlled attenuator circuit which, in order to avoid audible switching clicks in audio equipment, employs current-controlled switches. A switch is switched on by means of a gradually increasing control current and a switch to be switched off is turned off by means of a gradually decreasing control current.

Signal transfer device having a transfer characteristic which is

A low distortion amplifier arrangement includes an amplifier having an inverting input, a non-inverting input, and an output, a first impedance coupled between the output and the inverting input, and a second impedance coupled between an input terminal of the amplifier arrangement and the amplifier inverting input. An impedance network is coupled between the inverting and the non-inverting inputs of the amplifier. The impedance value of said impedance network substantially corresponds to the impedance value of the parallel connection of the first impedance and the second impedance, but with opposite sign. The gain of the amplifier arrangement is independent of the gain of the amplifier and corresponds to the ratio of the impedance values of said first and second impedances to produce an amplifier arrangement with a very low distortion.

Amplifier arrangement with very low distortion

An analog-digital converter in which a capacitor is charged or discharged by a reference current with the aid of transistor switches, a continuous current flows through the capacitor which is determined by an input difference voltage. One side of the capacitor is connected via a comparator to a flip-flop, to which flip-flop a clock signal is applied and which flip-flop drives the transistor switches. The other side of the capacitor is connected to the first input of a differential amplifier, which differential amplifier forms part of a negative feedback loop which maintains the voltage at the first input of the differential amplifier equal to the voltage which is applied to the second input of the differential amplifier.

Analog-digital converter

A measuring arrangement for measuring the effective value of an a.c. signal. Said a.c. signal is applied to a first thermal convertor, while a d.c. output signal is applied to a second thermal convertor. The two thermal convertors differentially drive a differential amplifier, which at its outputs delivers the d.c. output signal. For values of the d.c. output signal which are smaller than a threshold value, a negative feedback signal which linearly depends on said d.c. output signal is applied via an additional negative-feedback network to at least one of the inputs of the differential amplifier. This facilitates zero-point adjustment, and also allows the measuring speed to be increased.

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Eindhoven, Netherlands

Theodorus J Van Kessel