Abstract: Community antenna television arrangement for the reception and distribution of TV signals and digital audio signals, in particular signals which are transmitted per satellite, including a head-end connected to a receiving antenna and a signal distribution network, a time-division multiplex signal which comprises the digital audio signals in a time-multiplex distribution, being applied to the head-end, which time-division multiplex signal is modulated on a sound carrier, the bit rate of the digital audio signals to be distributed being reduced in the head-end of the community antenna television arrangement by a TDM/FDM conversion in order to reduce signal echoes.

Abstract: A system for transmitting n-level data signals by means of an angle-modulated carrier having a constant amplitude and a continuous phase. The constant amplitude enables amplification in non-linear transmitter output stages. Associated with the n-levels are k(k>n) phase variations in accordance with such a rule, depending on preceding phase variations, that the spectrum of the angle-modulated signal becomes narrower. In a symbol interval the phase of the carrier changes by an amount from the sequence extending from -(k-1).pi./n to (k+1).pi./n in increments of 2.pi./n. The receiver is formed by a differential n-phase receiver. The system is used inter alia for radio transmission of digital information.

Abstract: A receiver for angle-modulated signals of the type a sin((.omega.)t+.phi.(t)), comprising a frequency transposition stage (3) incorporating a local oscillator (3-1). A frequency shift .DELTA..omega. of the local oscillator relative to the carrier frequency .omega. may cause the angle modulation signal .phi.(t) to become faded. An argument detector (4) produces the signal [.phi.(t)+(.DELTA..omega.)t] which is differentiated by a differentiator (6) to provide the signal [d.phi.(t)/dt+.DELTA..omega.]. A DC-shift detector (7) determines the DC-component .DELTA..omega. of this signal. This component is integrated by an integrator (8) to provide the signal (.DELTA..omega.)t, which is thereafter subtracted by difference producer (5) from the output signal of the argument detector (4) to provide a clear angle modulation signal.

Abstract: A system having a transmitter and a receiver for transmitting binary data signals of a given symbol rate, an angle-modulated carrier signal of a substantially constant amplitude and a continuous phase being generated in the modulation stage of the transmitter, and the transmitted modulated signal being orthogonally, coherently demodulated in the receiver. The modulation stage of the transmitter is arranged so that the phase of the modulated signal changes in each symbol interval by an amount from the sequence -.pi./2, -.pi./4, 0, .pi./4, .pi./2 (rad.), which amount is determined for the relevant symbol interval by at least two successive data symbols, and the value of the phase within the relevant symbol interval is determined by a filtered version of at least these two succesive data symbols.