Abstract: In a combination of an amplifier (2,5,6) and a signal-dependent voltage supply source (16-23) coupled thereto, a portion of the signal from a signal source (1) is applied by an amplifier (9) to a comparator (16), the output signal of which controls a limiter (20-21). A portion of the output signal thereof is applied as a feedback signal to a second input of the comparator (16) by means of a low-pass filter (22) and a feedback network (23) in series. The feedback loop thus formed is arranged so that it oscillates at a comparatively high frequency. A signal-dependent modulation of the pulse width and/or the pulse density then occurs at the limiter output. A supply voltage for the amplifier is derived from the output of the filter (22). Owing to the high feedback factor of the feedback loop at the signal frequencies the supply voltage can adequately follow the output signal of the amplifier independently of component tolerances and any load variations.

Abstract: A delta modulator comprising a feedback loop incorporating a cascade arrangement formed by a difference producer, a loop filter, a two-level quantizer, a clock pulse-controlled sampler and a feedback path. In order to optimize the signal/quantization noise ratio the minimum phase loop filter has such a phase characteristic that the phase shift in the feedback loop caused by the time delay of the sampler is replenished to approximately 180.degree. with a certain margin, in a frequency range up to a certain cut-off frequency, the phase of the loop filter being constant above the cut-off frequency.

Abstract: Apparatus for modulating the output signal of a converter for converting electric signals into other signals, for example optical signals. An analog signal is applied to a subtraction device (6) the output signal of which controls a limiter (7). The binary output signal thereof controls the semiconductor laser diode (1) which is coupled to a photo-sensitive detector (3) for producing a feedback signal. After being amplified in a broad-band amplifier (9) and integrated in an integrator (13), this feedback signal is applied to the subtraction device (6), so that the feedback signal is subtracted from the analog signal. Variations in the optical output signal due to a non-linear conversion characteristic of the laser diode (1) and due to an optical retroaction of the fibre (2) on the laser diode, as well as output noise and signal-dependent amplitude variations, are reduced by the negative feedback.

Abstract: A delay network, having a chain of all-pass sections, each comprising two separate branches, a resistive and a capacitive branch, which terminate in amplifiers with negligible signal consumption whose output signals are combined. This enables an analog delay network to be realized in integrated circuit technology.

Abstract: A phase-locked loop circuit in which the phase offset error arising from imperfections in the balance of the phase comparator is reduced to a minimum by a special construction of the phase comparator. The quasi-static phase error of the loop is then reduced to very low values so that the loop is particularly suited for recovering the clock frequency from synchronous pulse signals having clock frequencies of several hundred MHz.

Abstract: A transmission system for pulse signals of fixed clock frequency having repeaters located in the transmission path, each of which is provided with an adjustable equalizing amplifier, a pulse regenerator and a clock extraction circuit. In addition to the pulse signals a pilot signal synchronized with the clock frequency is transmitted which is synchronously mixed with a local pilot signal derived from the clock extraction circuit. From the mixing product an adjusting signal for automatic equalization is derived which is reliable under all conditions. The resulting simplicity of structure and implementation of the equalizing amplifier renders the transmission system particularly suited for pulse signals at a very high clock frequency.

Abstract: In a wide-band transistor amplifier having a cascade arrangement of several of a special type of gain cell a low dissipation, a relatively small number of coupling and decoupling elements and a high value of gain-bandwidth product is obtained by interconnecting the gain cells in a special way. This wide-band amplifier is quite suited for monolithic integration and for construction as a distributed equalizing amplifier.

Abstract: A transmission system for pulse signals of fixed clock frequency with regenerative repeaters located in the transmission path, each being provided with a pulse regenerator and a clock extraction circuit recovering the clock frequency for the control of the pulse regenerator from the received pulse signals with the aid of a frequency selective circuit. The use of a special type of frequency selective circuit results, especially in transmission systems having a large number of regenerative repeaters, in a considerable reduction of the phase jitter of the recovered clock signal in the receiver without detrimentally influencing the acquisition of the clock frequency in the individual regenerative repeaters.