Abstract: In a method of estimating a signal-to-interference ratio (SIR), a first average channel power per slot of a first channel that is under a fading environment is estimated. A second average channel power per slot of a second channel that is under a fading environment substantially the same as the first channel is estimated, wherein the first and second channels are multiplexed. A second signal power attenuation ratio of the second channel is calculated using the second average power per slot of the second channel. A third average power per slot of the first channel is calculated using the first average power per slot of the first channel and a reciprocal of the second signal power attenuation ratio of the second channel.

Abstract: A system and method is disclosed for providing real time signal to noise computation for a 100 Mb Ethernet physical layer device. A slicer module obtains a slicer error signal in the physical layer device and generates a signal that represents a square of the slicer error signal. A variance computation unit uses the signal that represents the square of the slicer error signal to calculate a value of variance of a histogram of the physical layer device by continuously accumulating a plurality of values of the square of the slicer error signal for a selected period of time. A real time signal to noise ratio is then computed using the calculated value of the variance of the histogram of the physical layer device.

Abstract: Disclosed herein is a method for characterizing interference in a radio communication system including a plurality of radio transceiver stations configured to communicate with user equipments, the method including: measuring, by a user equipment in radio communication with a serving transceiver station, quantities indicative of interference from interfering transceiver stations; sending the measured quantities to the serving transceiver station; associating at least one codebook with the serving transceiver station, the codebook including a number of codewords each representing a respective quantized interference situation in an area covered by the serving transceiver station; and identifying in the codebook a codeword representative of the quantities measured by the user equipment.

Abstract: A system is presented that monitors the quality of a communications channel with mirror receivers. A first receiver and a second receiver, coupled in parallel with the first receiver, receive a data signal transmitted over the communications channel. The second receiver generates an output signal. A signal integrity (SI) processor manipulates the output signal in order to determine the quality of the communications channel. The SI processor samples a phase-shifted version of the output signal, which has a phase shifted relative to a zero reference phase, and analyzes the phase-shifted version of the output signal for bit errors. In an embodiment, the SI processor manipulates the output signal to extract an eye diagram indicative of the quality of the communications channel. The SI processor non-intrusively determines the quality of the communications channel using the second receiver.

Abstract: In a communication system, when packet data units (PDUs) to be transmitted from a transmitter apparatus are modulated according to Orthogonal Frequency Division Multiplexing (OFDM), the waveforms representing the modulated PDUs will experience different peak to average ratio values (PAR) making the PDUs differently sensitive to non-ideal transmitter characteristics. To minimize errors in the transmitted PDUs, at least two PDUs (304, 305, 306) are scrambled and modulated in parallel and substantially simultaneously in the transmitter (100), and the PAR values of the at least two PDUs (304, 305, 306) are determined at each transmit instance. The measured PAR values of the at least two PDUs are compared in a scheduler (310), and the scheduler selects for transmission the PDU with the lowest PAR value. The scheduler (310) then instructs the transmitter (100) to transmit the selected PDU.

Abstract: A communications device comprises a receiver for receiving an input signal operably coupled to analogue to digital converter logic. The analogue to digital converter logic is operably coupled to control logic via a signal analyser arranged to analyse a converted received input signal, output from the analogue to digital converter logic to determine at least one characteristic of the received signal. The control logic is arranged to vary a dynamic range of the analogue to digital converter logic depending on the at least one determined characteristic of the received input signal.

Abstract: A noise sampling detector suitable for portable electronic devices is disclosed. The detector may detect noise, transmitter signals, spurs, and/or interference. In one embodiment, a detector can include: a load portion; an antenna pattern shaping portion coupled to the load portion, where the antenna pattern shaping portion includes meandering segments of variable lengths and/or widths; and an impedance matching circuit coupled to the antenna pattern shaping portion.

Abstract: A method and apparatus for improving performance in communication systems is provided. In one implementation, initial encoded data that has been encoded with a rateless code is received. A quality metric is determined for a communication medium on which the initial encoded data has been received. A modulation scheme used in sending the initial encoded data on the communication medium is identified. An estimate is determined, based on the identified modulation scheme and the determined quality metric, of an amount of mutual information being received per unit of received encoded data. An amount of mutual information being received is determined, based on the determined estimate.

Abstract: In a digital wireless communication device having an error correction function, the circuit quality is quickly detected with maintained accuracy. The circuit quality to such an extent that a bit error rate (BER) is slightly degraded (10?10 to 10?12) is quickly detected with maintained accuracy by monitoring the circuit quality based on a C/N error pulse into which C/N information scaling a carrier-to-noise power ratio (C/N) of a received signal has been converted.

Abstract: A signal modulation apparatus, a signal modulation method and a computer program product thereof are provided. The signal modulation apparatus is used in a communication framework consisting of a plurality of communication systems. The communication systems comprise a first communication system having a first antenna and a second communication system having a second antenna. The signal modulation apparatus is configured to generate isolation information to modulate a power of a first antenna according to specification information of the first communication system, specification information of the second communication system, information of the first antenna, information of the second antenna, distance information of the first antenna and the second antenna, and test information.

Abstract: Impulse noise from nearby or intense electrical sources can disrupt communications over digital subscriber lines (DSL). The characterization of the nature, timing and length of impulse noise sources present on a DSL loop is a critical first step in mitigating the effect of impulse noise on DSL communications. DSL standards provide histograms for impulse length and inter-arrival time of impulses. These histograms can be used to derive the nature, maximum frequency and other statistics related to impulse noise on a DSL line.

Abstract: A method for selecting transmission parameters for a data transmission is provided comprising determining, for each of a plurality of transmission parameter settings, a data throughput that is expected when the transmission parameter setting is used for data transmission, wherein the data throughput is determined using a pre-generated mapping of transmission parameter settings to data throughputs and selecting a transmission parameter setting based on the determined expected data throughputs.

Abstract: A method of removing noise and interference from a signal by receiving the signal, calculating a joint time-frequency domain of the signal, estimating instantaneous frequencies of the joint time-frequency domain, modifying each estimated instantaneous frequency, if necessary, to correspond to a frequency of the joint time-frequency domain to which it most closely compares, redistributing the elements within the joint time-frequency domain according to the estimated instantaneous frequencies as modified, computing a magnitude for each element in the joint time-frequency domain as redistributed, plotting the results as the time-frequency representation of the signal, identifying in the plot any noise and interference components in the received signal, eliminating from the redistributed joint time-frequency domain elements that correspond to noise and interference, and recovering a signal devoid of noise and interference from the modified redistributed joint time-frequency domain.

Abstract: In a method for estimating a signal-to-noise ratio (SNR) of an orthogonal frequency division multiplexing (OFDM) wireless mobile communication system, noise is estimated from adjacent received signals of at least two adjacent subcarriers and received signals of subcarriers, noise power is calculated by calculating a mean square value of the estimated noise by summing squares of the estimated noise, a mean square value of the received signals is calculated by summing squares of the received signals, signal power is calculated by subtracting the noise power from the mean square value of the received signals, and the SNR is calculated using the signal power and the noise power. Thus, the method of the present invention having low complexity can estimate an SNR efficiently regardless of channel changes on a frequency axis when one OFDM symbol includes preamble data.

Abstract: A communications apparatus which ensures a predetermined communication quality even when an external environment changes dynamically, and enhances a throughput for overall system, thereby achieving favorable transmission efficiency. A communications apparatus having a receiver and a transmitter and carries out sending/receiving by use of a pulse train is provided with a communication environment measuring section to measure a communication status based on an output from the receiver. The transmitter is configured such that it transmits a transmission signal, in which the transmission rate of data to be transmitted and the pulse energy have been controlled in association with each other, according to a result of the measurement.

Abstract: A radio communication system minimizes power consumption against noises. The system includes a first radio terminal (10A) with a first transmitter (40A) for transmitting a first data indicative of a specific event, and a second radio terminal (40A) with a battery (14B) and a receiver (20B). The first radio terminal (10A) includes a first bit interpolator (32A) which inserts a check bit pattern of “01010101” at a predetermined cycle into one frame of the first data. The second radio terminal (10B) has a second power controller (60B) which intermittently activates the second receiver (20B) at predetermined intervals in order to receive the bit-interpolated data from the first transmitter.

Abstract: Embodiments related to FEXT estimation and signaling in vectored systems are described and depicted herein.

Abstract: A method for transmitting channel quality information based on a differential scheme is disclosed. When channel quality information of a predetermined number of sub-bands selected by a receiver in a frequency selective channel is transmitted, total average channel information is transmitted. Channel information of the selected sub-bands is transmitted as sub-band differential information associated with average channel information. In this case, the sub-band differential information may be denoted by a specific value contained in a differential-value range including only positive (+) values. If at least two channel quality information is transmitted by a MIMO system, channel quality information of one channel is transmitted, then channel quality information of the other channel is transmitted as spatial differential information. In this case, the spatial differential information is denoted by a specific value contained in a differential-value range asymmetrical on the basis of “0”.

Abstract: A modem testing system is provided for testing interoperability of plural items of customer premises equipment (CPEs) (10) and plural central offices (COs) (60). The modem testing system includes a line simulator (50), a switch (40), and a controller (30). The line simulator is connected to the CPEs and COs for simulating various types of lines and noise statuses. The switch is connected to the line simulator, the CPEs, and the COs for switching connections between the CPEs and the COs. The controller is connected to the line simulator, the switch, the CPEs, and the COs for controlling the switch to set up communications between the CPEs and the COs according to a mapping list, and controlling the line simulator to simulate various types of lines and noises statuses. An exemplary modem testing method is also provided.

Abstract: A signal transmission apparatus comprises a first signal transmission section configured to transmit a first signal for performing measurement of characteristics of a transmission line to the transmission line. A reflection characteristic measurement section is configured to measure a reflection characteristic of the transmission line. A pass characteristic measurement section is configured to measure a pass characteristic of the transmission line. A determination section is configured to determine a transmission clock frequency based upon the reflection characteristic. A second signal transmission section is configured to modulate information and to transmit a second signal obtained by the modulation to the transmission line. A second signal receiving section is configured to receive and to demodulate the second signal which has been transmitted by the second signal transmission section and has passed the transmission line.

Abstract: A method of optimizing a communication system for receiving and processing an input communication signal includes selecting a first noise margin m to be applied against an external noise present on the input communication signal. The method further includes selecting a second noise margin mi to be applied against an internal noise introduced on the communications signal by the communication system. The second noise margin is a predetermined function of the first noise margin. The method also includes calculating a virtual noise to signal ratio that is a combination of an external noise to signal ratio NSRe, an internal noise to signal ratio NSRi, the first noise margin and the second noise margin. The method further includes adjusting one or more system parameters so as to maintain the virtual noise to signal ratio at a predetermined margin above a required noise to signal ratio.

Abstract: A method for accessing aircraft interference path loss in an aircraft. A plurality of radio frequency signals that are stepped through a plurality of frequencies in a frequency range is transmitted from a plurality of locations within an interior of the aircraft. Radio frequency signals present at a receive antenna are received in response to transmitting the plurality of radio frequency signals to form a plurality of measurements. An average of averages curve is generated from the plurality of measurements. A peak to average ratio is identified. Field uniformity is identified. A standard error for the average of averages curve is determined. An upper bound for the aircraft interference path loss in the aircraft is predicted using the average of averages curve, the peak to average ration, the field uniformity, and the standard error.

Abstract: A terminal for receiving digital broadcast signals includes signal receiving components for receiving a digital broadcast signal, and a first error rate detection unit for detecting a first bit error rate (BER) of the digital broadcast signal before the digital broadcast signal is decoded by a decoder. The terminal also includes a second error rate detection unit for detecting a second bit error rate (BER) of the digital broadcast signal after the digital broadcast signal is decoded by the decoder, and a packet error rate detection unit for detecting packet error rate (PER) of the digital broadcast signal. The terminal typically further includes a controller for determining reception quality of the digital broadcast signal based upon a value of the first BER, or the second BER, or the PER. A method for determining signal reception quality includes receiving a digital broadcast signal, detecting the BER, and determining reception quality of the digital broadcast signal based upon a value of the BER.

Abstract: A method for generating a series of output signals represented by a series of measurement signals which is particularly useful in the compensation for jatter, missing spurious pulses or plates when applied to the processing of signals from a speed probe monitoring the speed of a rotating bladed shaft. The method includes the steps of predicting a value for a first measurement signal from a historical measurement signal value, generating a first output signal from the predicted value of the first measurement signal; comparing the measurement signal to its predicted value, and: if the measurement signal is within a predetermined range of acceptable values, using the first measurement signal to predict a value for a second measurement signal; if the measurement signal is outside the pre-determined range of acceptable values, using the first predicted value to predict a second measurement signal, and generating a second output signal from the predicted value of the second measurement signal.

Abstract: A method and apparatus for dynamically adjusting power of a transmitter is herein described. A transmitter transmits a pattern to a receiver at a differential voltage. The length of the pattern, in one embodiment, is selected to be a reasonable length training pattern, as not to incur an extremely long training phase. If errors are detected at the receiver in the pattern, the transmitter steps the differential voltage until errors are not detected in the pattern at the receiver. The differential voltage, where no errors are detected, is scaled by a proportion of a target confidence level to a measured confidence level associated with the reasonable length training pattern. As a result, a training phase is potentially reduced and power is saved while not sacrificing confidence levels in error rates in the data exchange between the transmitter and receiver.

Abstract: A method implemented by a user equipment includes selecting a first estimate of a signal-to-noise (SNR) ratio, calculating a first amplitude and first noise variance, calculating a second amplitude and a second noise variance, calculating a second SNR, calculating a resolution value, adjusting the first SNR, and performing estimation iterations until the resolution value is equal to a predetermined value.

Abstract: An object of the present invention is to provide a radio quality estimation system, a base station, a mobile station, and a radio quality estimation method whereby, regardless of influence of fading, a radio quality of a predetermined measurement period is more accurately estimated. An interference power calculator calculates an interference-signal power of each of local estimation intervals which are parts of the predetermined estimation interval. An SIR calculator calculates an SIR of the predetermined estimation interval based on the interference-signal powers calculated by the interference power calculator.

Abstract: A method for channel estimation includes: loading a combination of signals sent on other lines over a line of a channel; measuring a signal-to-noise ratio (SNR) of the loaded line; and calculating crosstalk channels of the loaded line according to a coefficient of the combination of signals sent on other lines and the measured SNR. Accordingly, a device and system for channel estimation are provided. The technical solution of the present invention may be used for relevant systems such as an x Digital Subscriber Line (xDSL) system.

Abstract: A method and apparatus for generating a signal to noise ratio (SNR) estimate. A conditional probability distribution function (CPDF) is rectified to suppress the condition, thereby creating a biased CPDF. Conditional offset moments are computed through an analysis of the asymmetry generated by the rectification. The conditional offset moments are then utilized to reduce the bias generated by the rectification to enhance the SNR estimate.

Abstract: Data transmission is disclosed over a transmission channel that is subject to narrowband interferers. An increased overall bit or data transmission rate is achieved by an exemplary method of determining a channel capacity of plural sub-channels of the transmission channel based on a net background noise power estimation. The net background noise power contains only white noise-like contributions and excludes, to a reasonable extent, noise contributions or signal power from narrowband interferers. Hence, the net background noise power can be reduced. For example, an Orthogonal Frequency Division Multiplex (OFDM) signal code construction or bit allocation scheme can be chosen that provides for optimized data transmission at a data rate that approximates or approaches the more realistic channel capacity of an individual sub-channel, resulting in an increased overall bit or data transmission rate.

Abstract: A statistical value update unit calculates the fluctuation of measurement data. A filtering processing unit extracts a normal white noise component from the fluctuation of the measurement data using an adaptive lattice filter. A statistical test unit determines whether or not the variance of the normal white noise component is out of a predetermined scope in reference distribution. A change decision unit detects a stationary change of the status of a target system based on a detection ratio of an outlier.

Abstract: A SINR estimator receiving a symbol stream has a delay element coupled to the symbol stream to produce a delayed symbol stream, which is also coupled to a conjugator. A first multiplier forms a product from the symbol stream and the output of the conjugator, thereafter summing these values over an interval L and scaling by L to form a correlated power estimate Cn. A second multiplier forms a product from the symbol stream which is multiplied by the conjugate of the input, thereafter summing these values over the preamble interval 2L and scaling by 2L to form a non-correlated power estimate Pn. Cn and Pn are compared to generate an SINR estimate.

Abstract: A method and apparatus for estimating interference and noise power in an orthogonal frequency division multiplexing/orthogonal frequency division multiple access/discrete multi-tone (OFDM/OFDMA/DMT) system is disclosed. A correlator correlates a plurality of sub-carriers with a preset reference sequence on an element-by-element basis and outputs a result of the correlation. A signal noise producer calculates a difference between a correlation value associated with each of the plurality of sub-carriers output from the correlator and a correlation value produced from at least one adjacent sub-carrier and outputs a result of the calculation. An interference and noise power producer produce interference and noise power from the difference between the correlation values calculated by the signal noise producer.

Abstract: In applications where data is transmitted in frames of symbols and the transmission medium is such that the probability of correct reception of symbols is, on the average, not uniform for different symbols in a frame, transmission of test frames enables creation of information about the different probabilities of correct reception, and that information is employed by the transmitter to control the manner in which symbols are transmitted so as to ameliorate the effects of the different probabilities of correct reception.

Abstract: One or more median filter circuits are used to filter radio link control measurements corresponding to one or more radio link parameters of interest, such as received signal quality or round trip delay measurements, such as might be used by a base station to trigger mobile station handoff. As such measurements are particularly susceptible to measurement outliers arising from rapid but short-lived changes in radio link propagation paths, for example, the application of median filtering to such measurements is particularly advantageous. That is, by operation of median filtering, which is a non-linear filtering process, outliers in a stream of control measurements, such as are caused by instantaneous changes in channel fading or other propagation phenomena, are discarded rather than averaged in with the other measurements. Non-linear filtering as implemented by exemplary median filtering does not impair or otherwise limit the bandwidth of the underlying control measurements.

Abstract: Insight and rules are needed for how to handle scheduling in a way meaningful for network operation is explained, such as what transmissions can be delayed for scheduling and which cannot be delayed for scheduling, and how grouped transmissions can be used for interference avoidance. Certain embodiments of the present invention provide a solution to these and other problems. In certain embodiments of the present invention, for example, users are grouped according to criteria which may be indirectly related to interference but are nevertheless different from interference. Thus, for example, certain embodiments of the present invention use expected receive or transmit signal strength or use MCS as grouping criteria.

Abstract: In an apparatus for estimating a Carrier-to-Interference-and-Noise Ratio (CINR) in a communication system, received signals are blocked based on sub-carriers with similar channel characteristics. Interference and noise levels and true received signal levels are computed on a block-by-block basis from the blocked received signals. CINRs are estimated on a block-by-block basis using ratios between the computed interference and noise levels and the computed true received signal levels. The apparatus can estimate a CINR for all channels even when the channel characteristics of the sub-carriers of the received signals are not similar to each other.

Abstract: The present invention provides procedures for computing Forward Error Correction (FEC) parameters given a set of constraints on maximum interleaver memory, maximum interleaver depth, maximum codeword size, maximum number of check bytes, maximum number of FEC codewords per Discrete Multi-Tone (DMT) symbol, and minimum number of DMT symbols that the FEC must correct, as well as any constraints imposed by the interleaver. These procedures are implemented on a computational engine in a modem, enabling it to achieve optimal performance in all cases. In addition these procedures can be applied as part of any bit loading algorithm to determine the optimal FEC parameters, taking into account the Signal-to-Noise Ratio (SNR) profile, the FEC coding gain, the constraints of the framer, and any application specific constraints.

Abstract: The measurement of far-end crosstalk (FEXT) in a Digital Subscriber Line communications is instrumental in the ability of using a multiple input multiple output (MIMO) pre-coder to cancel FEXT. A reliable robust back channel for transmission of error is instrumental to provide error samples for the proper operation of a MIMO pre-coder. Bins can be dedicated to insure bandwidth from the customer premises equipment (CPE) to the central office (CO). By increasing the margin used in the bins, robustness can be added to this back channel between the CPE and CO.

Abstract: A system for measuring air quality in wireless networks. In particular implementations, a method includes computing an interference severity level for a plurality of interference sources detected at an access point; aggregating one or more of the computed interference severity levels relative to the access point; and computing an air quality metric for the access point, wherein the air quality metric based at least in part on an equation: 1—aggregated interference severity level.

Abstract: A decision feedback-based communication system comprising a unit for computing an estimated Error Propagation Probability (EPP) for a plurality of received signals, and a unit for receiving the EPP estimation and improving detected signal quality based thereon. The system can be a coded system or an uncoded system.

Abstract: A 10GBASE-T transceiver that is capable of performing cable diagnostics. The transceiver is a physical layer device (PHY) that has four transceiver sections. Each section includes an input path and an output path. The input path generally includes a receiver, an analog-to-digital converter, a far end cross talk/near end cross talk canceller section, an alien noise canceller section, and an equalizer section. The output path includes a coding and preconditioning section, a digital-to-analog converter, and a transmitter. A substantial savings can be realized by utilizing the same elements that perform data communication to perform cable diagnostics. The diagnostics might occur before a link is formed or after a link is formed and may be based on test signals only or on data signals or communications. A first PHY might perform diagnostics alone or in combination with a second PHY which is in communication with the first as a link partner.

Abstract: A wireless link simulator includes, in sequence, a digital transmit device under test (TX-DUT), a wireless link simulator, and a digital receive device under test (RX-DUT). The wireless link simulator includes, in sequence, a transmitter IQ imbalance generator, a power amplifier non-linearity generator, a noise floor generator, a multi-path channel generator, a receive noise generator, a frequency offset generator, a phase noise generator, a receive IQ imbalance generator, and a DC offset generator. Each of the generators may be individually varied to determine the receiver sensitivity to each of these effects and associated parameters.

Abstract: Adaptive modulation part (1) modulates a signal in a modulation scheme selected based on a modulation mode, switch (2) selects a radio scheme congenial to the modulation scheme in which the signal is modulated. When the selected radio scheme is single-carrier scheme, single-carrier generation part (3) generates a single-carrier signal. When the selected radio scheme is a multicarrier scheme, multicarrier generation part (4) generates a multicarrier signal, the generated single-carrier signal or multicarrier signal is converted into a carrier band signal by quadrature modulation part (5), and the converted signal is amplified by transmission amplifier (6).

Abstract: An apparatus and method are provided for estimating a Carrier-to-Interference-and-Noise Ratio (CINR) in a communication system based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In the communication system, all base stations boost a power level for a preamble or pilot by B dB. Accordingly, a received signal power level and a received interference level are boosted by B dB, but a noise level is not boosted. Transmission power for a preamble or pilot interval is boosted as compared with that for the data interval. After an interference and noise level is estimated from a preamble or pilot, the interference and noise level estimate of the preamble or pilot is corrected by taking into account a boosting level of the preamble or pilot.

Abstract: A user equipment includes an estimator. The estimator is configured to select a first estimate of a signal-to-noise (SNR) ratio, calculate a first amplitude and first noise variance, calculate a second amplitude and a second noise variance, calculate a second SNR, calculate a resolution value, adjust the first SNR, and perform estimation iterations until the resolution value is equal to a predetermined value.

Abstract: Filtered digital information representative of the power of an output signal from an amplifier is generated, and control information from a setpoint representative of a desired power for the output signal is generated from the desired response time for the establishment of the power and from a model to be followed for the establishment. In addition, a gain control and a bias current control are established for each initial variable-gain amplifier from the filtered digital information, from the control information and from a polynomial digital regulation of the RST type whose polynomial coefficients are determined from input parameters comprising characteristics of each variable-gain amplifier and from characteristics of the filter generating the filtered digital information.

Abstract: A channel estimation device is provided to achieve high-precision channel estimation in a MIMO or multicarrier wireless receiver. This channel estimation device is used in the wireless receiver that receives pilot signals through reception antennas. The pilot signals are modulated by a multicarrier method and are transmitted from transmission antennas. The pilot signals are orthogonal to one another. The channel estimation device includes: an estimation unit that determines a channel estimate value for each unit time slot and each unit sub carrier; and an averaging unit that averages the channel estimate values over time slots including a target time slot and sub carriers including a target sub carrier, thereby determining an average channel estimate value.

Abstract: Certain embodiments utilize raw signals to estimate channel quality, as contrasted to utilizing equalized signals or after channel estimation. For example, signal quality may be estimated by calculating powers of pilot sub-carriers and null sub-carriers of the raw signals. To mitigate channel effect, certain embodiments utilize first and/or second order differentiation schemes.

Abstract: There is provided a measuring apparatus for measuring a signal-to-noise ratio of a discrete waveform which is output from an AD converter in response to an input signal, where the signal-to-noise ratio indicates a ratio of a signal component of the input signal to noise generated by the AD converter. The measuring apparatus includes a spectrum compensating section that receives a spectrum of the discrete waveform output from the AD converter, and compensates the received spectrum in accordance with a non-symmetric sideband between an upper sideband and a lower sideband of the received spectrum, where the upper and lower sidebands are defined with respect to a fundamental frequency of the input signal, and a phase noise waveform calculating section that calculates a phase noise waveform of the discrete waveform based on the spectrum which has been compensated by the spectrum compensating section.