Abstract: Translating to a hardware description language (HDL) from an architecture description language (ADL) is disclosed. An architecture description that is written in the ADL and has a hierarchical organization is received. Decoders are generated, described in the HDL, from the architecture description written in the ADL. Control signals are generated, described in the HDL, from the architecture description written in the ADL. The decoders are configured to output the control signals and the control signals are input to functional units in order to preserve the hierarchical organization of the architecture description written in the ADL.

Abstract: In a ring communication system comprising selectively connectable data stations, each station has connecting circuitry including a phase-locked loop arrangement (111) which is frozen at its current frequency and phase in response to a signal interruption caused by a station insertion or removal operation. Control logic (113) generates a freeze control signal in dependence of the signal energy status on input lines (75). This control signal activates gates (149, 151) and switches (155, 157) to interrupt change control signals of the phase-locked loop circuitry and to keep an oscillator control voltage at a given value. The control logic also provides an auxiliary data signal during the freeze interval which is applied to the ring to keep stations downstream in synchronism. By this method and arrangement, undesired reactions and excursions of the phase-locked loop circuitry in response to a signal energy outage are prevented, and synchronization can be rapidly regained after station insertion or removal.

Abstract: A mosaic printer is made secure from unauthorized interception of data by falsifying the needle drive pulse current magnitude and sequence so that electromagnetic leakage radiation cannot be used to determine the alphanumeric data being printed. This falsification is accomplished by a compensation device having compensators energized each print cycle in addition to the printer needle drives in a reciprocal or a pseudorandom manner. The compensators have current consumption characteristics nominally identical to the needle drives and produce substantially identical radiation pulses, making it impossible to correlate the radiated pulse format with the symbol being printed.

Abstract: Apparatus for indicating whether a correlation tracking system such as a phase-locked-loop has locked onto a periodic signal or not, utilizing a quadri-correlation circuit and digitalizers for the in-phase and the quadrature correlation signals, and logic circuitry for detecting the direction of transitions in the output state combinations of the digitalizers, and for adding the detector output signal rates for obtaining lock.

Abstract: A black and white facsimile communication system wherein the document to be transmitted is scanned line by line, the scanner signals are sampled to obtain pulse sequences having a constant number of pulses for every line. The pulse sequences are converted into codewords for redundancy reduction. The codewords are transmitted and, in the receiver, reconverted into pulse sequences which control reproduction. Before reproduction every pulse sequence obtained by reconversion is tested whether it contains the correct number of pulses. If that is not the case, the last reproduced line is reproduced again instead of the line received with an error.