Abstract: A calculating apparatus that calculates a characteristic of a target signal, including an input section that receives a bit error or a sampling timing, and a calculating section that calculates sampling timings over a range in which the bit error rate is less than a designated value or a bit error rate at a designated sampling timing, by using a relational expression between the sampling timing and the bit error rate. A transmission model for transmitting a signal having jitter includes a random component and a deterministic component having a prescribed probability density distribution. The relational expression is achieved by substituting, as parameters, a standard deviation of a random component and a peak-to-peak value of a deterministic component in a jitter of the target signal.

Abstract: A jitter measuring apparatus measures timing jitter of a signal-under-test. The jitter measuring apparatus includes a pulse generator for outputting a pulse signal of a predetermined pulse width for an edge of the signal-under-test, and a jitter measuring sub-unit for extracting the timing jitter on the basis of a duty ratio of each cycle of the signal output by the pulse generator.

Abstract: Provided is a jitter measurement apparatus, including a sampling section that samples a signal under measurement having a cycle T, a waveform reconfiguring section that shapes a reconfigured waveform having the cycle T by rearranging ordinal ranks of sample values sampled by the sampling section, a distribution generating section that generates a timing distribution of edges in the reconfigured waveform, and a statistical value calculating section that calculates a statistical value of the timing distribution. The sampling section may sample the signal under measurement having the cycle T a certain number of times N while the signal under measurement repeats for M cycles, where M and N are coprime.

Abstract: A deterministic component identifying apparatus identifies a distribution shape of a deterministic component included in a probability density function supplied thereto. The apparatus includes a standard deviation calculating section that calculates a standard deviation of the probability density function, a spectrum calculating section that calculates a spectrum of the probability density function, a null frequency detecting section that detects a null frequency of the spectrum, and a ratio calculating section that calculates a ratio between a top portion and a bottom portion of a distribution of the deterministic component, based on the standard deviation of the probability density function and the null frequency of the spectrum.

Abstract: A jitter measurement apparatus that measures timing jitter of a signal under measurement having a prescribed repeating pattern includes a sampling section that coherently samples the signal under measurement within a prescribed measurement duration; a waveform reconfiguring section that rearranges ordinal ranks of data values sampled by the sampling section to generate a reconfigured waveform that is a reproduction of a waveform of the signal under measurement; an analytic signal generating section that converts the reconfigured waveform into a complex analytic signal; and a jitter measuring section that measures jitter of the signal under measurement based on the analytic signal.

Abstract: Provided is a jitter injection circuit that generates a jittery signal including jitter, including a plurality of delay circuits that are connected in a cascading manner and that each sequentially delay a supplied reference signal by a preset delay amount and a signal generating section that generates each edge of the jittery signal according to a timing of the signal output by each delay circuit. In the jitter injection circuit the delay amount of at least one delay circuit is set to be a value different from an integer multiple of an average period of the jittery signal.

Abstract: Provided is a phase detecting apparatus that detects a phase difference between signals, comprising a phase comparing section that sequentially delays a second input signal relative to a first input signal, according to a set value, and that compares a phase of the second input signal to a phase of the first input signal each time a relative phase between the input signals changes; and a delay adjusting section that adjusts in advance a delay amount of a signal in the phase comparing section.

Abstract: There is provided a transmission system in which a data sequence is transmitted. The transmission system includes a transmitter that generates a transmission signal by converting pieces of data included in the data sequence into data waveforms each of which has (i) a level signal whose signal level is determined by a value of a corresponding one of the pieces of data and (ii) a timing edge indicating a timing to obtain the level signal, and transmits the generated transmission signal, and a receiver that detects the signal level of each of the data waveforms of the received transmission signal at the timing designated by the timing edge of the each data waveform, and outputs a data value corresponding to the detected signal level.

Abstract: Provided is a jitter injection circuit that generates a jittery signal including jitter, including a plurality of delay circuits that receive a supplied reference signal in parallel and that each delay the received reference signal by a preset delay amount and a signal generating section that generates each edge of the jittery signal according to a timing of the signal output by each delay circuit. In the jitter injection circuit the delay amount of at least one delay circuit is set to be a value different from an integer multiple of an average period of the jittery signal.

Abstract: A communication system in which a signal is transferred includes a transmitter that transmits a signal, a receiver that receives a signal transmitted thereto, and an adaptive equalizer that generates a compensated signal by compensating degradation of the signal to be received by the receiver. The adaptive equalizer includes a signal compensating section that generates the compensated signal by passing therethrough the signal to be received by the receiver, a jitter measuring section that measures jitter of the compensated signal output from the signal compensating section, and an adjusting section that adjusts a characteristic of the signal compensating section so as to reduce the jitter of the compensated signal which is measured by the jitter measuring section.

Abstract: There is provided a jitter measuring apparatus for measuring jitter in a signal-under-measurement having a first pulse generator for detecting edges of the data-signal-under-measurement to output a first pulse signal having a pulse width set in advance corresponding to the edge, a second pulse generator for detecting boundaries of data sections where data values do not change in the data-signal-under-measurement to output a second pulse signal having a pulse width set in advance corresponding to timing of the detected boundaries of the data sections, a filter for removing carrier frequency components of said data-signal-under-measurement from first and second pulse signals and a jitter calculating section for calculating timing jitter in the data-signal-under-measurement based on the first and second pulse signals.

Abstract: Provided is an evaluation apparatus that evaluates a characteristic of a propagation apparatus propagating a signal, comprising an output signal measuring section that measures a probability density function expressing a probability density distribution of jitter of an output signal passed by the propagation apparatus; an isolating section that isolates at least one of a random component of a jitter component and a deterministic component of the jitter component in the jitter of the output signal, from the probability density function of the jitter of the output signal; and an evaluating section that evaluates the characteristic of the propagation apparatus based on the jitter component isolated by the isolating section.

Abstract: There is provided a delay circuit that delays and outputs a given input signal. The delay circuit includes a first delaying section that delays the input signal, a second delaying section that further delays the input signal delayed by the first delaying section, and a delay setting section that sets a time delay in the second delaying section at a timing delayed by a predetermined time to a timing setting a time delay in the first delaying section.

Abstract: A jitter measurement apparatus measures a jitter of a data signal having a substantially constant data rate. The jitter measurement apparatus includes therein a signal converting section that generates a clock signal based on the data signal, where the clock signal retains timings of data transition edges of the data signal at which a data value of the data signal transits and has edges whose cycle is substantially equal to the data rate, an analytic signal generating section that generates an analytic signal represented by a complex number based on the clock signal, and a jitter measuring section that measures the jitter of the data signal based on the analytic signal.

Abstract: Provided is a calculating apparatus that calculates a characteristic of a target signal, comprising a designating section that receives a designation of either a bit error rate or a sampling timing; and a calculating section that calculates a range of sampling timings over which the bit error rate is less than a designated value or a bit error rate at a designated sampling timing by using a relational expression between the sampling timing and the bit error rate in a transmission model for transmitting a signal having jitter that includes a random component and a deterministic component having a prescribed probability density distribution, the relational expression achieved by substituting, as parameters, a standard deviation of a random component in jitter of the target signal and a peak-to-peak value of a deterministic component in the jitter of the target signal.

Abstract: Provided is a deterministic component identifying apparatus that identifies a distribution shape of a deterministic component included in a probability density function supplied thereto, comprising a standard deviation calculating section that calculates a standard deviation of the probability density function; a spectrum calculating section that calculates a spectrum of the probability density function; a null frequency detecting section that detects a null frequency of the spectrum; and a ratio calculating section that calculates a ratio between a top portion and a bottom portion of a distribution of the deterministic component, based on the standard deviation of the probability density function and the null frequency of the spectrum.

Abstract: Provided is a deterministic component model determining apparatus that determines a type of a deterministic component included in a probability density function supplied thereto, comprising a standard deviation calculating section that calculates a standard deviation of the probability density function; a spectrum calculating section that calculates a spectrum of the probability density function; a null frequency detecting section that detects a null frequency of the spectrum; a theoretical value calculating section that calculates a theoretical value of a spectrum for each of a plurality of predetermined types of deterministic components, based on the null frequency; a measured value calculating section that calculates a measured value of the spectrum for the deterministic component included in the probability density function, based on the standard deviation and the spectrum; and a model determining section that determines the type of the deterministic component included in the probability density function

Abstract: There is provided a deterministic component model identifying apparatus for determining a type of a deterministic component contained in a probability density function supplied thereto.

Abstract: Provided is a digital modulator, including a carrier wave output section that outputs a carrier wave, a variable delay section that delays the carrier wave, and a delay amount setting section that sets a delay amount by which the variable delay section delays the carrier wave based on transmission data being transmitted by the carrier wave. The variable delay section may include a multi-stage delay buffer circuit in which delay buffers that delay an input signal by a unit shift amount are connected in a cascade connection, the multi-stage delay buffer circuit may receive the carrier wave at a first-stage delay buffer as input, and the delay amount setting section may include a multiplexer that selects either an output from the carrier wave output section or an output from each stage of the multi-stage delay buffer circuit.

Abstract: Provided is a jitter measurement apparatus, including a sampling section that samples a signal under measurement having a cycle T, a waveform reconfiguring section that shapes a reconfigured waveform having the cycle T by rearranging ordinal ranks of sample values sampled by the sampling section, a distribution generating section that generates a timing distribution of edges in the reconfigured waveform, and a statistical value calculating section that calculates a statistical value of the timing distribution. The sampling section may sample the signal under measurement having the cycle T a certain number of times N while the signal under measurement repeats for M cycles, where M and N are coprime.