Abstract: A method of measuring skew between signals from an asynchronous integrated flash memory controller (IFC) includes connecting input/output (I/O) pins of the IFC to cycle based test equipment (ATE). The ATE applies a pattern of test signals as input drive to the IFC. Relative to the test cycle, the earliest delay time at which output signals from all of the I/O pins first correspond with expected results, and the latest delay time at which the output signals still correspond with the expected results are measured. The difference between the latest and the earliest delay times is compared with a limit value and a comparison report is generated.

Abstract: Disclosed are various embodiments providing processing circuitry that generates an output for each clock cycle of a clock signal using a logic block, the logic block being powered by a supply voltage. The processing circuitry detects whether the output has stabilized at a point in time before the end of a clock cycle of the clock signal, the point in time being based at least upon a delay line. In response to detecting whether the output has stabilized at a point in time, the processing circuitry dynamically adjusts at least one of the supply voltage or the frequency of the clock signal.

Abstract: A semiconductor device-under-test (DUT) may be tested by an automated test system that processes test programs specifying a number of edges per tester cycle that may be greater than the number of edges the tester is capable of generating. The test system may include circuitry that reduces the number of edges in each cycle of a test program based on data specifying operation of the tester in that cycle and/or a prior cycle. Such a reduction simplifies the circuitry required to implement an edge generator by reducing the total number of timing verniers per channel. Nonetheless, flexibility in programming the test system is retained.

Abstract: A memory interface enables AC characterization under test conditions without requiring the use of Automated Test Equipment (ATE) and functional patterns. The memory controller may be configured to generate output patterns through the test interface and create a loopback path for input specification testing using an external stressed-eye random number generator and checker. As a result, the memory interface may be evaluated for electrical and timing specifications under a relatively simple test setup and test procedure through the test interface (JTAG), as opposed to a complex processor program that sets up a similar memory access pattern on Automated Test Equipment (ATE).

Abstract: Provided is a method and apparatus for aligning a first local oscillator (LO) clock generated by a controllable LO clock generator in a first radio frequency (RF) path with a second LO clock in a second RF path. The apparatus includes a synchronization channel configured to exchange a synchronization clock between the first and second RF paths, a phase detector configured to measure a phase alignment between the first and second LO clocks, and a loop filter configured to drive the controllable LO clock generators using the phase alignment. Also provided is a time to digital converter. The time to digital converter includes a D flip-flop for sampling first and second input clocks with a third clock, and a counter configured to synchronously increment the resulting samples and create a digital proportional value representing the delay between the first and second clocks.

Abstract: Techniques for calibration of high-speed interleaved analog-to-digital converter (ADC) arrays are presented. A transceiver comprises an ADC component that comprises an array of sub-ADCs that can be interleaved to facilitate high-speed data communications. The ADC component processes signals received from a remote transmitter to facilitate recovering the received data. The transceiver can comprise a calibration component that determines transfer characteristics of the communication channel or medium between the transceiver and the remote transmitter, and the transfer characteristics of the remote transmitter to each of the sub-ADCs of the array, based on the recovered data.

Abstract: A processor is described comprising: instruction failure logic to perform a plurality of operations in response to a detected instruction execution failure, the instruction failure logic to be used for instructions which have complex failure modes and which are expected to have a failure frequency above a threshold, wherein the operations include: detecting an instruction execution failure and determining a reason for the failure; storing failure data in a destination register to indicate the failure and to specify details associated with the failure; and allowing application program code to read the failure data and responsively take one or more actions responsive to the failure, wherein the instruction failure logic performs its operations without invocation of an exception handler or switching to a low level domain on a system which employs hierarchical protection domains.

Abstract: An information processing apparatus is provided which includes a transmission unit for transmitting a query request for querying another device for a count value held by such other device, a reception unit for receiving a return of the count value from such other device, a correction unit for performing, at a predetermined period, correction processing for synchronizing sampling frequency with such other device based on the received count value, and a reproduction unit for reproducing content in synchronization with such other device based on the sampling frequency. The correction unit corrects by taking into account a Round Trip Time between the transmission of the query request and the reception of the return and residual difference occurred at a previous correction time.

Abstract: A memory module may have a redrive circuit having a plurality of redrive paths, a memory device, and a deskew circuit. The deskew circuit may be separate from the plurality of redrive paths. The deskew circuit may be coupled between the plurality of redrive paths and the memory device to selectively deskew data received in the redrive circuit.

Abstract: A circuit and method for implementing a adaptive bit-leveling function in an integrated circuit interface is disclosed. During a calibration operation, a pre-loaded data bit pattern is continuously sent from a sending device and is continuously read from an external bus by a receiving device. A programmable delay line both advances and delays each individual data bit relative to a sampling point in time, and delay counts relative to a reference point in time are recorded for different sampled data bit values, enabling a delay to be determined that best samples a data bit at its midpoint. During the advancing and delaying of a data bit, jitter on the data bit signal may cause an ambiguity in the determination of the midpoint, and solutions are disclosed for detecting jitter and for resolving a midpoint for sampling a data bit even in the presence of the jitter.

Abstract: A method and apparatus for generating an accurate clock generator timing source, comprising minimal jitter, excellent resolution, and an extended calibration range, for use, for example, in a system requiring accurate low power operation. In particular, a clock generation system is adapted to receive a generated clock input, a reference clock input, and an adjustment parameter comprising a sign bit and p data bits. The calibration logic system is further adapted to output and modify a calibrated clock, using distributed pulse modification. The adjustment parameter may be automatically generated.

Abstract: The invention uses a PRBS pattern generated by transmitter (serializer) as training At the receiver side, following receiver outputs, a synchronous capturing module is used to capture multiple lanes simultaneously. The captured data is used to calculate the PRBS distance for different lanes. After the distances are obtained, the one with largest latency is used as a reference, to calculate the relative latency with each other lane. This relative latency is further used to calculate the number of shifts for Barrel Shifter and word shifter.

Abstract: Method and system of adjusting a first phase shift between a first data signal and a clock signal at a sending device. First and second test signals representing first and second test data, respectively, are transmitted to a receiving device. The test signals have respective phase shifts relative to the clock signal. An error detection code is calculated from first and second received data carried by the transmitted signals. The error detection code is transmitted from the receiving device to the sending device. An estimated first received data is calculated from the error detection code, wherein the estimated first received data are calculated under the assumption that the second received data are identical to the second test data. The first phase shift is adjusted on the basis of a comparison of the estimated first received data and the first test data.

Abstract: For runtime dynamic performance skew elimination in a computer environment, an exemplary computer environment is configured for calculating a rank heats by utilizing a plurality of fine-grained statistics collected at an extent granularity, including considering bandwidth (BW) and input/outputs per second (IOPS) metrics. An adaptive data placement plan is generated to relocate the data.

Abstract: Provided is a test apparatus that tests a device under test having a plurality of output terminals. The test apparatus comprises an executing section that executes a test command sequence for testing the device under test; a storage section that stores a plurality of pieces of setting data designating one or more output terminals among the plurality of output terminals; a detecting section that detects whether a value of an output signal from an output terminal designated by one of the pieces of setting data matches an expected value; and a selecting section that selects different pieces of setting data in the storage section when at least two detection commands, which change execution sequencing of the test command sequence according to the detection results of the detecting section, are executed, and supplies the selected pieces of setting data to the detecting section.

Abstract: Techniques and mechanisms for evaluating I/O buffer circuits. In an embodiment, test rounds are performed for a device including the I/O buffer circuits, each of the test rounds comprising a respective loop-back test for each of the I/O buffer circuits. Each of the test rounds corresponds to a different respective delay between a transmit clock signal and a receive clock signal. In another embodiment, a first test round indicates a failure condition for at least one I/O buffer circuit and a second test round indicates the failure condition for each of the I/O buffer circuits. Evaluation of the I/O buffer circuits determines whether the device satisfies a test condition, where the determining is based on a difference between the delay corresponding to the first test round and the delay corresponding to the second test round.

Abstract: A receiver timing error recovery loop expands the bandwidth of a received signal and determines the timing error based on the bandwidth expanded received signal.

Abstract: A sampling phase selection method for a data stream is provided, wherein the data stream has a variable data rate in a fixed time period. The method comprises generating a calibration signal, wherein the time interval of the calibration signal is longer than the fixed time period of the data stream, generating a first clock sequence and a subsequent second clock sequence, wherein the first and the second clock sequence are composed of a plurality of continuous clock phases and the number of the clock phases of the first clock sequence are the same as that of the clock phases of the second clock sequence, selecting one of the phases of the first and the second clock sequence, in turn, to provide a sampling phase, performing a plurality of samplings on the data stream to generate a flag signal, and selecting a final sampling phase according to the flag signals with different sampling phases.

Abstract: An apparatus that compensates for misalignment on a synchronous data bus. The apparatus includes a resistor network and a synchronous receiver disposed within a receiving device. The resistor network is configured to provide a ratio signal that indicates an amount to delay a data bit signal associated with a data group, where the data bit signal is transmitted by a transmitting device along with a data strobe signal. The synchronous receiver receives the data bit and the data strobe signals, and includes a delay-locked loop (DLL). The DLL is coupled to the ratio signal, and is configured generate a delayed data bit signal, where the DLL adds the amount of delay to the data bit signal to generate the delayed data bit signal, and where the delayed bit signal is delayed relative to the data strobe signal by the amount, thus allowing for proper reception of the data bit signal.

Abstract: A counter configuration operates in cooperation with a delay configuration such that the counter configuration counts an input interval based on a given clock speed and a given clock interval while the delay configuration provides an enhanced data output that is greater than what would otherwise be provided by the given clock speed. The counter configuration counts responsive to a selected edge in the clock interval. An apparatus in the form of a correction arrangement and an associated method are configured to monitor at least the delay configuration output for detecting a particular time relationship between an endpoint of the input interval and a nearest occurrence of the selected clock edge in the given clock signal that is indicative of at least a potential error in the enhanced data output and determining if the potential error is an actual error for subsequent use in correcting the enhanced data output.

Abstract: A skew adjusting apparatus includes: latching circuits that latch other signals in synchronism with transition timing of the signal level of a reference signal among signals transmitted with a plurality of communication cables; delay elements that are provided on the plurality of communication cables, and delay the signals transmitted with the plurality of communication cables, respectively; and a controller that controls the delay elements based on the outputs of the latching circuits to adjust skews between the signals.

Abstract: A clock generator generates a clock signal used for sampling a received signal by a comparator which compares the received signal to a reference. A phase shifter adjusts the phase of the first clock signal and a controller adjusts the phase of the clock signal to maximize the vertical eye opening of the signal at the sampling time. In an example embodiment, the phase of the clock signal is adjusted in a first direction and a measure of vertical eye opening of the signal is compared to a previous measure. If the measure of vertical eye opening has increased the signal another phase adjustment is made in the same direction and if the vertical eye opening of the signal has decreased a further phase adjustment in the opposite direction is made. By increasing the vertical eye opening of the signal the signal-to-noise ratio of the received signal is improved.

Abstract: In accordance with embodiments of the present disclosure, an information handling system may include a processor, a first information handling resource communicatively coupled to the processor, and a second information handling resource communicatively coupled to the processor and the first information handling resource. The first information handling resource and the second information handling resource may be configured to, in concert determine an optimum delay between opposite polarity signals for differential signals communicated from the first information handling resource to the second information handling resource via a path comprising a differential pair and transmit data from the first information handling resource to the second information handling resource via the path by inserting a delay into one of the opposite polarity signals equal to the optimum delay.

Abstract: A method and a system for accurately calculating the timing margin in a clock and data recovery system (CDR) is provided that utilizes a singular path environment of hardware. The method entails adding an amount of jitter within the CDR to change the receiver phase. The amount of jitter is incrementally increased until a threshold level of bit errors occur. Based on the amount of jitter needed to cause the threshold level of bit errors, timing margin can be calculated.

Abstract: A delay controller includes an acquiring section that acquires synchronization timings indicating timings when a plurality of controllers, which control via a line a plurality of transmitters that transmit data, synchronously control the transmitters, a determining section that determines a reference synchronization timing serving as a reference for synchronization between the controllers, on the basis of the synchronization timings acquired by the acquiring section, and a synchronization information transmitting section that transmits synchronization information to the controllers, the synchronization information being used when the controllers receive data from each of the transmitters at the reference synchronization timing determined by the determining section.

Abstract: For runtime dynamic performance skew elimination in a computer environment, an exemplary computer environment is configured for calculating a rank heats by utilizing a plurality of fine-grained statistics collected at an extent granularity, including considering bandwidth (BW) and input/outputs per second (IOPS) metrics. An adaptive data placement plan is generated to relocate the data.

Abstract: Soft decision sections provisionally decide each modulated signal separated using an inverse matrix calculation of a channel fluctuation matrix at separation section. Signal point reduction sections reduce candidate signal points of a multiplexed modulated signal using the provisional decision results. Soft decision sections make a correct decision using the reduced candidate signal points and obtain received data of each modulated signal. This allows received data RA, RB with a good error rate characteristic to be obtained with a relatively small number of calculations without reducing data transmission efficiency.

Abstract: In one embodiment, a method of performing data training in a system including a memory controller and at least a first memory device including a group of memory banks is disclosed. The method includes providing a plurality of enabling states for the group of memory banks, wherein each enabling state is different and for each enabling state a set of the memory banks of the group is enabled and any remaining of the memory banks of the group are not enabled. The method further includes performing a first data training procedure that includes a series of first data training operations for the first memory device, each data training operation being performed for a different one of the plurality of enabling states, generating a noise profile based on the series of first data training operations, statistically analyzing the noise profile to select a reference enabling state of the group of memory banks, and performing a second data training procedure for the first memory device using the reference enabling state.

Abstract: For runtime dynamic performance skew elimination in a computer environment, an exemplary computer environment is configured for calculating a rank heats by utilizing a plurality of fine-grained statistics collected at an extent granularity, including considering bandwidth (BW) and input/outputs per second (IOPS) metrics. An adaptive data placement plan is generated to relocate the data.

Abstract: Sequential circuits with error-detection are provided. They may, for example, be used to replace traditional master-slave flip-flops, e.g., in critical path circuits to detect and initiate correction of late transitions at the input of the sequential. In some embodiments, such sequentials may comprise a transition detector with a time borrowing latch.

Abstract: Apparatus and methods are disclosed for decoding data stored on a data storage medium. A disclosed decoding method and decoder include a radial incoherence (RI) detector that increases the probability of detecting RI and improves the decoding performance in terms of the bit error rate of the decoded signal. RI is detected by comparing an input signal to the decoder against a RI threshold value and generating a RI-type signal. The RI detector may include a filter for filtering out noise and error in the RI-type signal, an adaptive threshold unit that adjusts the RI threshold value based upon the RI-type signal, a transition-based threshold unit that adjusts the RI threshold value based upon each transition in the input signal, or a path-based threshold unit that adjusts the RI threshold value based upon a best surviving path corresponding to the input signal, in combination or alone.

Abstract: An apparatus that compensates for misalignment on a synchronous data bus, including a resistor network, a transmitting device, and a receiving device. The resistor network indicates an amount to advance a synchronous data strobe associated with a data group. The transmitting device has a core clocks generator and a synchronous strobe driver. The core clocks generator advances a data strobe clock by the amount. The synchronous strobe driver employs the data strobe clock to generate the synchronous data strobe, where the synchronous data strobe is advanced also by the amount. The receiving device has a composite delay element and delay-locked loops (DLLs). The composite delay element equalizes delay paths within the receiving device, where the delay paths correspond to the synchronous data strobe that is received from the transmitting device.

Abstract: The real time processing supported by programmable control unit (RTP PCU) includes a method, a system and an apparatus for implementing programmable algorithms for analyzing a very wide range of low and high frequency wave-forms. The RTP PCU comprises sequential processing stages (SPS) for real time capturing and processing of in-coming wave-form and a programmable control unit (PCU) for controlling SPS operations and supporting adaptive signal analysis algorithms. The RTP PCU further comprises a circuit for Sequential Data Recovery from Multi Sampled Phase (SDR MSP).

Abstract: A programmatic time-gap defect correction apparatus and method corrects errors which may go undetected by a computer system. Buffer underruns or overruns, which may incur errors in data transfers, yet remain undetected and uncorrected in a computer system, are corrected by an error avoidance module in accordance with the invention. Bytes transferred to and from buffers, used by an I/O controllers to temporarily store data while being transferred between synchronous and asynchronous devices, are counted and an error condition is forced based on the count. If the count exceeds the capacity of the buffer, an error condition is forced, thereby reducing chances that errors are incurred into the data transfer.

Abstract: Systems and methods are disclosed for aligning multiple data bits by adjusting the timing of input lines for those data bits. Embodiments include a hierarchical structure for comparing the timing of multiple sets of bits. Other embodiments include aligning data bits from multiple chips in a 3D die stacking architecture.

Abstract: A system and method for loop timing update of energy efficient physical layer devices using subset communication techniques. During a quiet period during which a subset of communication channels are transitioned from an active mode to a low-power mode, circuitry in the active channel can be designed to track, on behalf of the inactive channels, the phase drift due to the frequency offset. This tracking of the frequency estimation error would reduce the time required to perform a timing update for the communication channels when transitioning back to the active mode.

Abstract: Some embodiments provide a configurable integrated circuit (IC) comprising multiple deskew circuits for delaying data passage. Each of the deskew circuits comprises a stepwise delay circuit with multiple outputs and an input selection circuit with multiple inputs. Multiple outputs connect to multiple inputs. In some embodiments the configurable IC is a subcycle reconfigurable IC. In some such embodiments each of the deskew circuits further includes a space-time load control circuit for commanding the stepwise delay circuit to load during a selected subcycle. In some embodiments the multiple deskew circuits send data to a trigger circuit. In some such embodiments the trigger circuit triggers a trace buffer to stop recording a data stream. In some such embodiments the trigger circuit triggers the trace buffer to stop after a programmable delay.

Abstract: An A/D conversion unit performs an A/D conversion operation twice during a hold period of an analog value. In a first conversion operation, the A/D conversion unit compares the analog value with a first reference voltage and outputs a comparison result as first converted data. In a second conversion operation, the A/D conversion unit compares the analog value with a second reference voltage and outputs a comparison result as second converted data. The second reference voltage is a voltage obtained by adding or subtracting a minimum resolution voltage to or from the first reference voltage. A digital processing unit averages errors of the first and second converted data by digital processing to detect an A/D conversion error, and feeds back a detection result to the A/D conversion unit as a control value to perform voltage control.

Abstract: A memory controller has a first interface, for connection to an external memory device; a second interface, for connection to at least one other component; and a third JTAG interface, for connection to an external user device. The memory controller further includes a processor, which performs calibration processes, in order to synchronize operations of the memory controller and the external memory device, and also runs test software for testing operation of the first interface and the external memory device, and for providing test results to the external user device over the third interface. The memory controller further includes an internal memory, for storing the instructions defining the test software.

Abstract: Disclosed herein are a deskew apparatus and method for Peripheral Component Interconnect (PCI) Express for compensating for a skew. The deskew apparatus includes a lane data input unit, a lane data alignment unit, and a lane data detection unit. The lane data input unit receives 18-bit data from each of lanes of the PCI Express. The lane data alignment unit aligns the 18-bit data using a COM symbol. The lane data detection unit detects a change in a state of alignment of the 18-bit data attributable to deletion or addition of an SKP symbol when the 18-bit data is aligned, and to perform synchronization between the lanes.

Abstract: A system and method for packet communication is disclosed. Echo in a received symbol stream may be reduced to produce an echo-reduced symbol stream. The echo-reduced symbol stream may be buffered and aligned according to a deskew signal to produce a deskewed symbol stream. The deskewed symbol stream may be decoded to produce a decoded packet.

Abstract: A semiconductor circuit for testing a logic circuit, the semiconductor circuit including: an exclusive OR circuit receiving an input testing signal to a circuit under testing and a output testing signal from the circuit under testing; a multiplexer receiving a result signal output from the exclusive OR circuit and a clock signal; and a flip-flop storing a logical value represented by a captured signal in synchronization with a multiplexed signal output from the multiplexer, the captured signal being selected from a entered signal (I) and a data signal that is output from another semiconductor circuit for testing.

Abstract: Embodiments of a time-to-digital converter are provided, comprising a delay stage matrix and a measurement circuit. The delay stage matrix comprises a first and a second delay lines coupled thereto, and is arranged to propagate a transition signal from a starting delay stage in the first and a second delay lines, wherein each of the first and second delay lines comprises a same number of delay stages coupled in series, each delay stage in one of the first and second delay lines is coupled to a corresponding delay stage in the other delay line and operative to generate a delayed signal. The measurement circuit is arranged to determine a time of the transition signal propagating along the delay stages by sampling the delayed signals using a measurement signal to generate and hold a digital representation of the time.

Abstract: A computer-readable, non-transitory medium stores a program that causes a computer to execute detecting in a circuit-under-test, a change in a signal output from each circuit element on a transmission-side, during one clock cycle on a reception-side at an asynchronous location; inputting to each circuit element on the reception-side, a signal for which a change is not detected at a detection time among detection times when a signal change is detected at the detecting and replacing with a random logic value, a signal for which a change has been detected at a detection time among the detection times and inputting the random logic value to each circuit element on the reception-side, in an action triggered by a rising edge of an operation clock on the reception-side after the one clock cycle; and outputting for each circuit element on the reception-side, an operation result obtained based on input at the inputting.

Abstract: A counter configuration operates in cooperation with a delay configuration such that the counter configuration counts an input interval based on a given clock speed and a given clock interval while the delay configuration provides an enhanced data output that is greater than what would otherwise be provided by the given clock speed. The counter configuration counts responsive to a selected edge in the clock interval. An apparatus in the form of a correction arrangement and an associated method are configured to monitor at least the delay configuration output for detecting a particular time relationship between an endpoint of the input interval and a nearest occurrence of the selected clock edge in the given clock signal that is indicative of at least a potential error in the enhanced data output and determining if the potential error is an actual error for subsequent use in correcting the enhanced data output.

Abstract: In a method of designing a system-on-chip including a tapless standard cell to which body biasing is applied, a slow corner timing parameter is adjusted to increase a slow corner of an operating speed distribution for the system-on-chip by reflecting forward body biasing, and a fast corner timing parameter is adjusted to decrease a fast corner of the operating speed distribution for the system-on-chip by reflecting reverse body biasing. The system-on-chip including the tapless standard cell is implemented based on the adjusted slow corner timing parameter corresponding to the increased slow corner and the adjusted fast corner timing parameter corresponding to the decreased fast corner. The slow corner timing parameter corresponds to a lowest value of an operating speed design window of the system-on-chip, and, the fast corner timing parameter corresponds to a highest value of the operating speed design window of the system-on-chip.

Abstract: A data reception device that receives scrambled and transmission data as received data and that descrambles and outputs the data after adjusting the timing with the transmitter has a descramble circuit 10 detect timing adjustment data included in a timing adjustment data set that adjusts the timing with the transmitter in the data which the descramble circuit 10 has not descrambled, and comprises an LFSR suspending signal generation circuit 9 that outputs a required number of LFSR suspending signals, after first normal timing adjustment data has been received, at the output timing of data received thereafter so as to simulate a situation as if a desired number of timing adjustment data included in the timing adjustment data set were received.

Abstract: A data recovery apparatus and method by using over-sampling are provided. The data recovery apparatus by using over-sampling includes an over-sampling module, a data regeneration unit, a phase alignment unit, a phase decision module, and an output data correction unit. The over-sampling module samples serial data according to a clock signal, so as to output M-bit data, in which each bit in the serial data is sampled N times. The phase alignment unit selects specific M-bit data from a P-bit signal output by the data regeneration unit, and distinguishes the specific M-bit data to X groups of N-bit signals. The phase decision module determines a direction of phase adjustment according to the specific M-bit data. The output data correction unit selects and outputs first or second recovery data constituted by first or second specific bits of each group of N-bit signal according to the direction of phase adjustment.

Abstract: A method for correcting the prediction of values of signal with time variation, in particular for navigation messages sent by the global satellite navigation systems, includes the following steps for the correction of the predictions of a parameter included in a received signal and varying in time: estimation of the prediction error based on a first batch of values estimated during a determined time period by comparing these values to the values previously predicted for the same determined time period, analysis of the predicted time-oriented series of prediction errors by a method for processing the signal and isolating the contributions of the systematic effects, and extrapolation of the behavior of the contributions of the systematic effects during the time period concerned and correction of the predictions using the duly extrapolated values.

Abstract: Apparatus and methods are disclosed for decoding data stored on a data storage medium. A disclosed decoding method and decoder include a radial incoherence (RI) detector that increases the probability of detecting RI and improves the decoding performance in terms of the bit error rate of the decoded signal. RI is detected by comparing an input signal to the decoder against a RI threshold value and generating a RI-type signal. The RI detector may include a filter for filtering out noise and error in the RI-type signal, an adaptive threshold unit that adjusts the RI threshold value based upon the RI-type signal, a transition-based threshold unit that adjusts the RI threshold value based upon each transition in the input signal, or a path-based threshold unit that adjusts the RI threshold value based upon a best surviving path corresponding to the input signal, in combination or alone.