Abstract: A circuit capable of handling all television sound transmission standards, including the "NICAM" standard. The circuit contains an analog antialiasing low-pass filter which is fed by the analog sound and video signal and followed by an analog-to-digital converter. The output of the latter is freed from the video signal by a filter circuit. The digital sound signal is applied to a phase splitter having a 0.degree. output and a 90.degree. output which are connected to a phase discriminator. An absolute-value output of the phase discriminator provides the amplitude-demodulated sound signal, while a phase-angle output feeds the DQPSK portion of a "NICAM" decoder and a differentiating stage, which delivers the frequency-modulated sound signal.

Abstract: In a pulse-density D/A or A/D converter, improved averaging of a pulse-density-modulated (PDM) signal in the presence of a jittering clock signal is achieved by applying the PDM signal to the serial input of an n-stage shift register whose parallel output serves to control n state signals. The shift register is driven by the clock signal. The n state signals are combined into a sum signal which feeds a low-pass filter. In preferred embodiments, the n state signals are weighted and/or isolated from the respective previous state and the following state by means of gate circuits.

Abstract: To realize the transfer function in a digital filter circuit:H(z)=b(1-z.sup.-kn)(1-z.sup.-n).sup.m-1 /(1-z.sup.-).sup.m,the following sections are cascaded: a multiplier for multiplying by 2.sup.-q ; m-1 integrators, each including a delay element which provides a delay equal to the period of the input sampling frequency; and mth integrator including a delay element which is reset by the output sampling clock; a sampling device which is switched at the output sampling clock rate; m-2 differentiators, each including a delay element which provides a delay equal to the period of the output sampling clock; and an (m-1)st differentiator including k delay elements which each provide a delay equal to the period of the output sampling clock.

Abstract: To raise the integration level of a video recorder, and to provide a uniform circuit concept suitable for all three color-television standard (PAL, NTSC, SECAM) which, in particular, requires only slight modifications for adaptation to the respective standard, signal processing is performed by fast digital circuits whose signals are stored on the recording medium not in digital form, but after digital-to-analog conversion. The composite color signal is converted into digital form by a fast analog-to-digital converter (aw) whose sampling signal (fc) has a fixed frequency (Fc) for all three color-television standards. Digital signal processing in the chroma channel is performed at a fixed subcarrier frequency (zt) for all three color-television standards which is an integral subharmonic of the sampling frequency (Fc).

Abstract: A digital frequency demodulator circuit works on the principle of determining the number of zero crossings of a band-limited input signal in a given period of time, in corresponding prior art analog circuits. The circuit includes an analog-to-digital converter, three delay elements, two edge detectors, an up/down counter, two arcsin read-only memories, a 1/2 multiplier and a multiple adder.

Abstract: An essentially digital circuit is disclosed in which a demodulated broadcast signal is digitized by an analog-to-digital converter and processed in three signal paths each including a tuned filter. The tuned filters have closely adjacent resonance frequencies, the same resonance curves, and the same resonance rises. The signals at the outputs of these three signal paths are so evaluated by means of four comparators and an RS flip-flop that the message tone signal appears at the Q output of the flip-flop only in the presence of the message tone frequency.

Abstract: A circuit for decoding broadcast traffic area signals according to the European standards utilizes digital circuitry to check for four criteria.

Abstract: A method for electronically monitoring parking lots and an electronic monitoring system for carrying out such method are disclosed. The method and system employs the use of a central control unit and a plurality of parking meters connected to the central control unit. The central control unit generates the time of day which is sent to and electronically stored in each parking meter. Depending on the number of coins inserted in a meter, an amount of time corresponding to the coins is calculated based on a given tariff. This time is added to the time of day to determine a time of departure. This time is indicated on indicating means provided at each meter. The actual time of day and the paid-for parking time are repeatedly compared until they are equal. At that time, the indicating means is cleared. A microprocessor, a variable storage element and a fixed storage element are provided at each meter to effect the necessary calculations and storage required. Additional features are also disclosed.