Adv Antest Corporation

Takeda Riken Kogyo Kabushiki Kaisha

Takeda Riker Co. Ltd.

Takayuki Nakajima

Noboru Akiyama

Tetsuo Sotome

Tetsuo Aoki

Kazuhiro Shimawaki

Katsumi Kobayashi

Kazutaka Osawa

Koji Nakagomi

Toshiro Takahashi

Kouichi Shiroyama

Bit error measurement system

A bit error measurement apparatus is capable of easily specifying pattern conditions which cause bit errors in an incoming signal pattern without measuring all of a test pattern by measuring a bit error rate at a selected position or region of a test pattern. The bit error measurement apparatus includes a test pattern generator which generates the test pattern for verifying the incoming signal to be tested, a verifier which receives the incoming signal and the test pattern and generates a bit error detection signal when the incoming signal and the test pattern disagree, a pattern position detector which detects a measurement region of the test pattern when receiving a synchronizing signal from the test pattern generator and generates a count enable signal corresponding to the detected measurement region, and an error counter which counts the bit error detection signal from the verifier based on the count enable signal from the pattern position detector.

Bit error rate measurement apparatus

An Nth one of N parallel sequences of low-speed data demultiplexed by a demultiplexer from high-speed input data in synchronization with a high-speed clock is compared by N comparators with N parallel sequences of reference patterns. The N parallel sequences of reference patterns are each generated in synchronization with a frequency divided clock obtained by frequency dividing the high-speed clock into 1/N. When any of the comparators provides a disagreement output at least once, one clock pulse is eliminated by a post-clock eliminating circuit from the divided clock so that the N sequences of reference patterns are each delayed by one bit. When a counter detects that any one of the comparators does not provide the disagreement signal for n consecutive bits, the sequence of reference patterns corresponding to this comparator and the Nth sequence of low-speed data are in synchronization with each other. Clock pulses of the number corresponding to the line position of the synchronized sequence of reference patterns are eliminated by a pre-clock eliminating circuit from the high-speed clock which is applied to the demultiplexer. By this, line positions of the N parallel sequences of low-speed data are sequentially shifted so that the Nth sequence of low-speed data assumes the same line position as that of the synchronized reference pattern, and as a result, the N parallel sequences of low-speed data are synchronized with the N parallel sequences of reference patterns, respectively.

Pattern synchronizing circuit

A logic analyzer applies test pattern signals from a pattern generator to a circuit under test and sequentially reads logic outputs into a memory. The output from the circuit under test when it reaches a predetermined logic state is input as an external control signal into the logic analyzer. A change command is generated from the pattern generator in relation to the generation of the test pattern signal. When the change command and the external control signal are obtained at the same time, and flow of the generation of the test pattern signals is changed to a predetermined flow.

Logic analyzer

Logic output data of a plurality of channels simultaneously obtained from a circuit under test are sequentially input in a memory, and after inputting a predetermined amount of such data, they are compared with corresponding expected values. The input data are divided into blocks, each including a plurality of data. Whether a mismatch is present in the comparison results for each block is indicated by a respective block element, and such block elements are displayed in a predetermined arrangement. It is also possible to provide a conventional list display including the input timing corresponding to the comparison results in which a mismatch is present.

A device for recognizing and measuring the lengths of glitches by sampling the input signal at fractions of a sampling clock, which clock has a period shorter than the period of pulses of the correct signal but longer than the glitch widths. The corrected input signal can be displayed, along with the glitch information.

Growing community of inventors

Gyoda, Japan

Takayuki Nakajima