Abstract:
In a decoder for decoding a serial data stream, employing an extracted base clock signal, synchronous with an input, coded, serial data stream, a fractionary frequency clock signal for sampling a decoded output data stream and a second fractionary clock signal for synthesizing a pre-decoded value produced by a first combinative logic network within a second combinative logic network to produce a decoded value that is sent to an output sampling flip-flop, a pipelined operation is implemented by momentarily storing the bits that are processed in the second combinative logic network and by anticipating of two full cycles of the synchronous base clock the processing by said first combinative network of the n-number of bits handled by the decoder. Each one of the two combinative logic networks is permitted to complete its decoding process within a full clock cycle in advance of the raising front of the outpunt sampling clock signal. With the same fabrication technology and therefore with the same propagation delay of the two combinative logic networks, the maximum operating spead may be doubled. A limited number of additional components are required to implement the pipelined operation of the invention.
Abstract:
A high-precision current generating circuit (1), particularly intended for a low-impedance circuit user, comprises a current mirror formed by a first (M1) and a second (M2) transistor of the MOS type, and a voltage regulator (4) having two terminals respectively connected to the drain terminals (D1,D2) of the two transistors (M1,M2) to maintain equal values of drain-source voltage (Vds1 and Vds2) on said transistors.
Abstract:
A programmable digital delay unit (20) presenting a number of cascade-connected delay blocks (22), and a number of controlled bypass elements (23, 24), one for each delay block (22). Each bypass element presents a bypass line (23) and a multiplexer (24) for selectively connecting the input or output of the respective delay block to the input of the next delay block (22). The delay blocks (22) are formed by the cascade connection of flip-flops (28), and the number of flip-flops (28) in each successive delay block (22), from the input of the delay unit (20), decreases in an arithmetic progression to the power of two, so that the selection signals (S₀-S₃) for the respective multiplexers (24) represent the bits of a digital word (M) specifying the required delay.
Abstract:
The device is to be used with a parallel architecture PRML reading apparatus comprising a variable-gain input amplifier (21), a low-pass analog filter (22), a transversal analog filter (23) and two distinct and parallel processing channels (24, 34) interposed between the transversal analog filter (23) and an RLL-NRZ decoder (25). The two processing channels (24, 34) comprise respective analog-digital converters (26, 36) and respective Viterbi detectors (27, 37) and operate according to sampling sequences that alternate with one another. The device (30) for processing the servo signals comprises a rectifier (31) connected to the outputs of said analog-digital converters (26, 36) and an integrator (32).
Abstract:
A shared register circuit structure coupled to data transmission lines through interfacing circuit means of the serial type which are connected to said registers by an address and data transmission bus. The structure includes at least one transmission line for select signals to alternatively use address information or data information.
Abstract:
The device comprises a variable-gain input amplifier (21), a low-pass analog filter (22), a transversal analog filter (23) and two distinct and parallel sampling channels (24, 34) interposed between the transversal analog filter (23) and an RLL-NRZ decoder (25). The two sampling channels (24, 34) comprise, each of them, an analog-digital converter (26, 36) and a Viterbi detector (27, 37) arranged in succession one after the other and operating according to sampling sequences that alternate with one another.
Abstract:
A circuit device (1) for phasing an oscillator (2), which comprises a multivibrator (3) having a transistor pair (Q1,Q2) with the emitters (E1,E2) coupled through a capacitor (C), comprises a normally open electronic switch (SW) controlled by a drive signal (IN) to close and inhibit the oscillator (2). This switch connects a voltage divider to the base of a transistor (Q7) connected to one (E2) of the emitters to interrupt the loop positive feedback of the oscillator (2) upon the voltage across the capacitor reaching a predetermined value.
Abstract:
A circuit particularly useful in AGC systems, produces an output current (I OUT ) which is proportional to the difference between a signal voltage (V AGC ) and a reference voltage (V R ) which is practically independent of temperature, by being a function of a ratio among actual values of integrated resistances and of a ratio among substantially temperature-stable voltages. The effects of temperature dependent value of integrated resistances and of temperature-dependent electrical characteristics of integrated semiconductor devices are compensated in order to produce the desired temperature-independent output current which may usefully be utilized for implementing an automatic gain control.
Abstract:
The invention relates to a basic cell (11) for comparing a first and a second digital signal (A, B), of the type having at least a first and a second input (I1, I2) and a first and a second output (O3, O4) and comprising at least one logic gate (14) receiving digital signals (A, B) at a first and a second signal input (IS1, IS2), and which comprises at least a first and a second controlled switch (P1, P2) inserted in parallel with each other between the output terminal of the logic gate (14) and the second output (O4) from the cell (11), the first switch (P1) being also connected between the first input (I1) and the first output (O3) of the cell (11) and the second switch (P2) being also connected between the second input (I2) and the second output (O4) of the cell (11). The invention also relates to a digital comparator (9) comprising a plurality of basic cells according to the invention.