Abstract: According to the present invention, an LFSR (300) has a propagation path (30) of serially coupled stages (65) and gates (80-3, 80-4), a feedforward path (10) of gates (80-1) and a feedback path (20) of gates (80-2). Depending on control signals (P, B, M), the gates (80-1, 80-2, 80-3, 80-4) are either active gates and operate as xor-gates or passive gates and operate as transfer gates. Feedforward and feedback signals are derived from input and output signals and can be supplied to any stage (65), so that characteristic polynomials of the input-output function are variable. The LFSR can fully or partly operate as a TYPE 1 or TYPE 2 LFSR which enables the execution of different algorithms on one hardware base.

Abstract: A linear feedback shift register (LFSR) of interest is modelled in software by replicating the LFSR in at least two identically configured model LFSRs. One model LFSR contains only the higher order initial bits of the LFSR of interest, with zeroes in the lower order bit positions, and the other model LFSR has only the lower order bits, with zeroes in the higher order bit positions. The model LFSRs are represented by respective tables of model LFSR output values that would be produced after a predetermined number of register shifts. The tables are accessed based on the initial value of the LFSR of interest, and the results of one table are combined with the results of the other table using an exclusive OR operator to thereby determine the output of the LFSR of interest.

Abstract: A linear feedback shift register includes a plurality of groups of flip-flops operated in synchronization with different clock signals and a condition satisfying circuit, provided in a wiring for connecting the pairs of flip-flops to each other, for satisfying conditions for one of linear feedback and generation of pseudorandom numbers.

Abstract: A feedback and shift unit is arranged to reduce to a minimum the number of processing steps required in a processor, such as a DSP, to achieve a particular operating function, such as a linear feedback shift or a stepping function used by encryption algorithms. The feedback and shift unit (50) comprises a linear feedback shift register (52) for storing a value of the feedback and shift unit. A tap register (56) stores a tap position indicator indicative of tap positions for the feedback and shift unit (50). An input provides data to the feedback and shift unit. A feedback matrix, coupled to receive the data from the input, provides data bits, generated in response to the data and the tap position indicator, that are shifted into the linear feedback shift register (52) to form the value stored therein.

Abstract: Microprocessor with registered clock counting for at a predetermined count producing a command signal of adjustable shape, and a hierarchical interrupt system for use therewith.A microprocessor comprises registered counting means that counts clock pulses. Upon attainment of a predetermined count it generates a command signal. Furthermore, it has a presettable input section that recurrently receives a variable preset count for downcounting, a secondary count section that is fed by said command signal output for counting successive command signals and under control of attainment of a predetermined count generates a secondary command signal on a secondary output. Next, a programmable registered pulse shaper mechanism under control of said secondary command signal executes serial shifting and outputs a shaped version of the secondary command signal. The above counting means is also associated to a parametrizeable interrupt priority mechanism.

Abstract: Apparatus for determining an integer power of a floating point number includes a shift register, a register file having a partial product register and a binary power register, a multiplier coupled to the register file for performing floating point multiply operations and a state machine for controlling the shift register, the register file and the multiplier. The state machine controls loading of initial values into the shift register and into the partial product register and the binary power register. The state machine controls execution of an integer power routine in which a new partial product value is determined by multiplying the contents of the partial product register by the contents of the binary power register if the LSB of the shift register is a 1. The partial product value is left unchanged if the LSB of the shift register is a 0. A new binary power value is determined by multiplying the contents of the binary power register by itself.

Abstract: A cell for a shift register comprises an input and an output connected to the line with which it is associated, the cell being parallel-connected on this line, and the output of the cell being separated from the rest of this cell by a tristate buffer circuit. This cell is made in such a way that the state of the inputs of the flip-flop circuits of the cell is never floating when these cells are insulated from the inputs of the cell.

Abstract: A circuitry with a pseudorandom noise generative function has a shift register for converting serial data into parallel data, an exclusive OR gate electrically connected to the shift register for fetching outputs from the shift register, the exclusive OR gate supplying exclusive ORed data to the shift register for use in generating a pseudorandom noise and a switch electrically connected to a data line transmitting serial digital data to be processed therein and an output of the exclusive OR gate for fetching the digital data and the exclusive ORed data respectively to select the serial digital data or the exclusive ORed data in response to a selective signal, the switch being electrically connected to the shift register for supplying the serial digital data or the exclusive ORed data to the shift register, thereby selecting a normal processing mode for the digital data or a pseudorandom noise generative mode for the exclusive ORed data.

Abstract: An energy saving clock signal generator is disclosed including a source of multi-phase waveform signals, a shift register, and a matrix switch. The waveform source provide four, six or more waveform signals to the shift register and the matrix switch. A number of progressive pulses N.sub.pp which are an integer multiple of the number of waveform signals are applied from the shift register to the matrix switch. The matrix switch responds to the waveform signals and the progressive pulse signals to produce a number of output clock signals which may be used to drive adiabatic logic circuits.

Abstract: A divider circuit provides an output signal having a frequency which is equal to the frequency of an input signal divided by an odd integer. This is achieved by feeding back the output from a binary counter through an AND gate, delay flip-flop and an OR gate so that one cycle is added the output of the binary counter.

Abstract: An image head in which storage time is shortened to ease block selection. The image head is provided with means for preventing the influence of storage time. For instance, minority carriers in the switching transistors for driving image blocks are extracted by amplification circuits. Another method is to drive the switching transistors in the non-saturation region to prevent accumulation of minority carriers. The image head is provided with block selection circuit comprising a shift register and a clock counter. The datum is set in the head data set bit of the shift register at the time of resetting. Whenever the clock counter counts clock signals for one image block, the counter will shift the datum by one bit. This datum drives the image blocks.

Abstract: A memory device having an addressing unit for addressing different values as addresses for input/output of data for each clock input during one cycle, and a memory inputting data at different designated addresses and cyclically outputting stored data. The memory device provides the operation of a shift register which is capable of determining the number of stages in accordance with the content of the addressing. By employing a memory which effects read-modify-write operations and by delivering input data obtained by the feedback of output data to this memory, the memory device can repeatedly output the same data. The memory device has a switch circuit operative in a first position for connecting an output of the memory to an input of the memory and in a second position for connecting the input of the memory to an external data source.

Abstract: The present invention provides a MRP generator comprising m MRP generating circuits connected in parallel which are operated at a 1/m clock speed and have a predetermined time relation to each other, wherein the MRP generating circuits are operated on the multiplex basis. The operating speed is improved.

Abstract: An all-optical circulating shift register encodes a received optical clock signal with a value derived from an encoded optical signal received at a control port thereof. A data input to the shift register is used to modify an encoded optical signal. The resulting encoded clock signal, appearing at an output port, is coupled back to the control port. The shift register uses the encoded clock signal at the control port to encode a subsequently-received clock signal. In one embodiment, the optical shift register is implemented using a Sagnac switch having a feedback path coupled between an output port and a control port of the Sagnac switch.

Abstract: The input nodes and output nodes of a plurality of storing circuits for storing plural-bit data are connected to one another to constitute a shift register. Each of the plurality of storing circuits includes a selection circuit for selecting 1-bit data from the plural-bit data according to a selection signal, a first latch circuit for latching the 1-bit data selected by the selection circuit in synchronism with a first clock signal, and a number of second latch circuits, which number corresponds to the number of bits of input data, for latching an output of the first latch circuit in synchronism with a plurality of second clock signals having phases different from that of the first clock signal. Data sequentially selected by the selection circuit is latched into the first latch circuit and then sequentially latched into the second latch circuit in a time-sharing fashion.

Abstract: An apparatus for counting the number of times that each of a large number of digital data patterns are present on a set of signal lines comprises a plurality of random access memories (RAMs) and a feedback means, arranged to form an array of linear feedback shift registers. The data to be analyzed is applied to the address inputs of the RAMs where it selects one of the linear feedback shift registers in the array. A data-valid signal associated with this data causes the selected linear feedback shift register to increment (or decrement) in its pseudo-random count. After the analysis period is over, the value at each address is read out and translated using a lookup table or other translating means from the pseudo-random code of the linear feedback shift register into a meaningful number. This result may then be displayed; for example, in a histogram. An improved feedback path for the linear feedback shift register avoids hang-up states and the need for initialization.

Abstract: A linear feedback shift register comprises a shift register formed of first to (n)th flipflops cascaded in such a manner that an output of a (i)th flipflop is connected to an input of a (i+1)th flipflop, where 2.ltoreq.n and 1.ltoreq.i.ltoreq.(n-1). First to (n)th output terminals are connected to outputs of the first to (n)th flipflops, respectively, and a clock terminal connected to a clock input of each of the flipflops. First to (n-1)th multiplexors of a "1-out-of-2" type are connected at their first input to a common preset value input terminal. Second inputs of the first to (n-1)th multiplexors are connected to the outputs of the first to (n-1)th flipflops, respectively. Each of the first to (n-1)th multiplexors has a control input connected to an individual control terminal.

Abstract: The present invention discloses a method of simulating the state of a TYPE I Linear Feedback Shift Register (LFSR) with information available as a result of a TYPE II LFSR implementation. This is accomplished by clocking a TYPE II LFSR to produce an output sequence. This sequence, or at least a portion thereof, is then stored in a storage medium, such as, for example, a shift register. Cascading a TYPE II LFSR output sequence into a shift register of length N, where N is the number of stages employed by the TYPE II LFSR, is the exact equivalent of a TYPE I LFSR. Accordingly, the shift register's contents will contain data corresponding to the state of a TYPE I LFSR.

Abstract: Apparatus for formation of a two-phase shift register bit that preserves noise margins, allows use of reduced standby power, requires only two clock phase signals to drive the system, and requires relatively few transistors for implementation. In one embodiment, the apparatus uses two modules that are substantially identical, each module using four transistors and requiring only a single clock phase signal for operation.

Abstract: A linear feedback shift register for use as a SONET data scrambler, operating in accordance with a generating polynomial of order n corresponding to an n by n transition matrix T, comprises k storage cells, where k>n, for producing a k-bit word, and linear feedback interconnections specified by a k by k transition matrix which is the k-th power of a k by k transition matrix constituted by the matrix T extended by k-n additional rows and columns. Specific examples are described for k=8 and k=16.

Abstract: A high speed digital programmable frequency divider (100) capable of frequency division by even and odd integers is disclosed herein. The frequency divider (100) of the present invention includes a waveform generator (200) for providing a periodic input waveform of a first period and the inverse thereof. The present invention further includes a clocked ring oscillator circuit (400) for providing first and second closed signal paths, in response to the input waveform, disposed to invert signals passing therethrough. The first and second signal paths have a common output node (499) and first and second propagation delays substantially equal to first and second integral multiples of the first period, respectively. In addition, the frequency divider (100) includes a programmable switch network (500) for opening the first and second signal paths to provide a periodic output waveform at the output node (499).

Abstract: A computer system clock generator generates several system clock signals which are in a tuned state at desired locations, thereby offsetting the effects of varying propagation delays among the system clock signals. A shift register ring has one of its taps selectively connected to its data input so that a series of logic high level and logic low level data is advanced through the shifting stages. A tap selector for each desired output signal logically combines the signals output from the appropriate taps to produce output clock signals having desired leading and trailing edges.

Abstract: For assisting the self-test of circuits with unequiplebable random patterns, a logic module is provided which is composed of two types of basic cells. Each basic cell contains a register cell and a sub-circuit composed of gates. Dependent on two control signals, the basic cells can be operated as a normal register, as a shift register or as a linear feedback shift register. In the operational mode as a linear feedback shift register, the logic module can be used as a random pattern generator. To this end, the logic module is divided into a first module and into a second module. The first module contains an interconnection of two types of basic cells and a combinational logic system which operates the one part of the output signals of the basic cell in accordance with a Boolean function. The operational result is supplied to a second module of identical basic cells which operates as a shift register.

Abstract: A bit-serial integrator includes the cascade combination of a bit-serial adder, a first bit-serial register and a second bit-serial register. Input signal is applied to one input of the adder and the output terminal of the second bit-serial register is coupled to a second input of the adder. A transparent latch is coupled to an output of the first bit-serial register and is conditioned to pass a predetermined number of sample bits and then to latch and output a particular sample bit for the duration of a sample period. The output of the latch is an integrated, scaled and truncated representation of the input signal.

Abstract: A programmable logic array (PLA) is described, having an integral decoder for selecting individual product lines. The integral decoder receives an input address by way of a set of buffers, which can be disabled so as to disable the integral decoder in normal operation. The buffers can be tested in their disabled state by means of an extra product line and extra output line. The extra product line is coupled to all the bit lines and to the extra output line, but not to any of the other output lines; the extra output line is coupled to the extra product line, but not to any of the other product lines. The buffers are tested by applying a sequence of addresses to the buffers in their disabled state, and observing the extra output line.

Abstract: A programmable logic array (PLA) is tested by applying a sliding-ones pattern to the bit lines from a circular shift register, and individual product lines are selected by applying a sequence of addresses from a linear feedback shift register (LFSR) to an integral decoder. Both the circular shift register and the LFSR are controlled by a common clock signal, avoiding the need for special synchronizing logic between them. The sequence lengths of the circular shift register and the LFSR are chosen to be coprime numbers. Thus, after a predetermined number of clock beats, all the crosspoints in the AND plane will have been individually tested.

Abstract: A programmable counter/timer is responsive to signals on a data line for producing signals on one or more output lines and includes a counter connected to the data line, a comparator connected to said counter for producing a control signal when said counter reaches a stored preselected value, and a qualification unit connected to the comparator, the qualification unit having a register for storing a logic state. The qualification unit is responsive to the control signal and the stored logic state for generating a signal on selected output lines when the counter reaches the predetermined stored value.

Abstract: Basic block shift registers are cascaded to form a fully programmable linear feedback shift register. Each of the basic block shift registers comprises a plurality of flip-flops, each of which includes control logic circuits. A polynomial equation is first fed into the linear feedback shift register for setting the respective flip-flops into predetermined logic states, which are used to encode messages to be shifted by the programmable linear feedback shift register. The number of flip-flops in the programmable linear feedback shift register can be varied, in accordance to the polynomial equation. Likewise, the polynomial equation also determines the number of times the programmable linear feedback shift register is to circulate the encoded messages.

Abstract: A frequency divide by n circuit, where n is an odd number, which includes means for splitting an incoming clock signal of frequency "f" into two non-overlapping complementary clock signals of frequency "f" and a shift register circuit. The shift register circuit is coupled to the signal splitting means and generates an output clock signal of frequency f/n in response to the two complementary clock signals. The output clock signal has a duty cycle equal to ((n-1)/2+D.sub.in)/n where D.sub.in is the duty cycle of the incoming clock signal. The output duty cycle is substantially independent of processing and operating conditions.

Abstract: A linear feedback shift register for inclusion in a VLSI circuit. During a test function for the VLSI circuit, the shift register can be programmed into an LSSD test mode, or two generate test patterns for the VLSI circuit, and to perform a corresponding signature analysis on hashing functions on the VLSI response to the test pattern. The linear feedback shift register can be programmed on the VLSI chip to perform any of these test functions. During normal VLSI circuit operation, the shift register is transparent to logic signals carried by the VLSI circuit.

Abstract: A serial input/output device includes a CMOS shift register having a plurality of D-type flip-flops. A detection circuit is associated with the CMOS shift register in order to detect whether the transfer data exists in the CMOS shift register. A gate circuit is provided for applying a transfer clock signal to the CMOS shift register only when the transfer data exists in the CMOS shift register, thereby minimizing the power consumption.

Abstract: A CMOS dynamic circulating-one shift register (10) is disclosed. One stage of a conventional N-stage circulating-one shift register is modified to become a control cell (14) which performs two additional functions, referred to as AUTOSET and AUTOCLEAR, to guarantee the existence of a single circulating logic one, after power up or during long-term use. To perform the AUTOCLEAR function, the output (Q3) of the control cell is connected to the CLR inputs of each of the remaining stages (12.sub.1 -12.sub.N-1) comprising the shift register. Therefore, when Q3 becomes a logic one, the remaining Q outputs are automatically cleared. The Q output from the control cell is also fed back as the D input to the first stage of the shift register (12.sub.1) to continue the circulation process.

Abstract: A variable frequency divider which includes a feedback shift register having a feedback gate of NOR type, a delay shift register for delaying output data from the feedback shift register by one clock, a control shift register having a control gate of AND type, a feedback circuit for feeding output data from the delay shift register and from the control shift register back to the feedback gate, and an expander which receives output data from the feedback shift register and produces a control signal according to said frequency dividing input and a frequency division ratio instruction signal. The control gate receives output data from the delay shift register and the control signal.

Abstract: A digital phase correlator compares the relative phase of two or more high-frequency clocks and corrects for any detected phase difference. The phase detector includes a pair of flip-flops whose output is an indication of which of the two clock pulses is leading the other. The output of the flip-flop controls, through a circuit including a rotating shift register and a multitap delay line, the delay introduced to one of the clocks in a manner such that the phase difference between the clocks is reduced to a minimum.

Abstract: A counter for counting pulses or dividing frequencies has a timing signal generator circuit for generating a timing signal at a predetermined interval. A hysteresis circuit has input-output characteristics defining a low input threshold level and a high input threshold level. A control circuit responds to the timing signal for generating at least three control signals having different levels including a first control signal having a level lower than the low input threshold level, a second control signal having a level higher than the high input threshold level, and a third control signal having an intermediate level which is between the low input threshold level and the high input threshold level. The counter has a very large capacity, simple construction, and is effective with both analog and digital signals.

Abstract: An easily testable integrated logic circuit utilizes a plurality of flip-flops to form a feedback shift register. In some embodiments, means are provided for selectively forming the flip-flops into a feedback shift register and for selectively supplying either the flip-flop contents or a random signal as partial inputs to the combinational logic circuit. In other embodiments, the feedback shift register is coupled to the AND logic array outputs of a combinational circuit which also includes and OR logic array.

Abstract: The device is associated with a logic apparatus thereto four lines are coupled for transmitting logic data having a predetermined frequency and supplying at the output thereof a multiplexed signal having a frequency which is four times the mentioned frequency and responsive to the control of the subject device which comprises a binary digit pseudo-random sequence source and four Exclusive-OR logic circuits coupling said source to said apparatus in such a way as to define for said multiplexed signal a pseudo-random sequence having a period 2.sup.7 -1, as the tributary data is T1=T2=T3=T4=".0.".

Abstract: A first logic circuit comprises coupling gate circuits driven by clock pulses of different phases, flip-flop circuits cascade-connected via the coupling gate circuits and feedback circuits for feeding back the outputs of the flip-flop circuits to the preceding stage flip-flop circuits, and generates pulse sequences of different phases. A second logic circuit further comprises latch circuits one for each of the flip-flop circuits, driven by the pulse sequences generated by the first logic circuit. Those logic circuits are useful to a successive approximation register of a successive approximation A/D converter.

Abstract: A register circuit which is used to asynchronously monitor any data or logical function (or functions) and be able to retain the status of the monitoring until the register is interrogated whereupon the register is automatically reset and able to receive or monitor another status signal.

Abstract: In utilizing frequency dividers at high frequencies the maximum operating frequency is determined by the delay time through the frequency divider. To minimize this delay time, a digital frequency divider is provided having a binary counter constructed of flip-flops and a shift register coupled to the output of said counter, wherein the output state of the shift register is forcibly reduced to a low level in response to a control signal for varying the number of frequency division of said counter. A circuit is also provided for feeding the input terminal of the flip-flop at the first stage of said counter with an OR output made up of the outputs of said shift register and said counter. Thus, the digital frequency divider can operate at a speed which is limited only by the toggle frequency of said flip-flop circuits.

Abstract: Apparatus for storing a periodic signal and for recycling complete cycles of such stored periodic signal. Samples of a periodic signal are stored in a memory at a time commencing at the start of a cycle of the periodic signal. A first control signal is produced at the start of each cycle of the periodic signal. A second control signal is produced when a predetermined portion of the storage means is full. In response to the second control signal and one of the first control signals produced after the second control signal, a signal is produced indicating the portion of the memory having samples of complete cycles of the periodic signal stored therein, such indicating signal being related to the amount of samples stored in the predetermined portion of the memory plus the amount of samples stored in such memory between the time of the second control signal and the time of the one of the first control signals produced after the second control signal.