76 results about "Test data compression" patented technology

This invention relates to one SOC test data compression method for multi-scanning linkage design in SOC test technique, which solves the problems of current method for large volume of data and non-module fault coverage rate with high cost and comprises the following steps: a, ranking the test set TD according to multiple links; b, using similar group to divide formula set; c, ranking each set of decreasing order; d, setting dictionary items number; e, zero plus index code, one plus test section to express each test section to get compressed test set TE.

The invention relates to a method for compressing the test data of integrated circuit, belonging to integrated circuit technical field, in particular to a deterministic self-test test data compressor. The invention comprises a phase shifter, a response compressor, a linear feedback shift register with a first and a second xor network while the shift register is connected with the phase shift, a scanning tree and a weigh random signal generating logic unit while the scan forest is connected with the phase shift, the gating signal end of the scan forest is connected with the weight random signal generating logic unit, and the output of the scan forest is connected with the response compressor. The invention further provides a deterministic self-test test data compression method. The invention uses the weight random signal generating logic unit to control the frequency of special signal of the input signal of the scan forest, to improve the fault coverage rate into the false random self-test process, to reduce the test data memory space generated by deterministic test vector.

The invention relates to a method for test data compression coding and decoding with same run length and a special decoding unit of a large scale integrated circuit, which belong to the technical field of integrated circuit test. In order to reduce the memory capacity of the test data and shorten the testing application time, the invention discloses a method for test data compression coding of the large scale integrated circuit, which comprises the following steps executed by a computer for storing programs: firstly, using a bit string as a basic unit to perform numerical statement on the runs of type 0 and type 1, partitioning the test data, and counting the length of the bit string; secondly, coding the length of the bit string by using two different types of coding modes so that the coding modes not only consider that variable length codes use short code words to replace long original bit strings but also consider the relativity between the runs, and the subsequent runs of continuous runs with the same run length can be further expressed by the short code words so as to achieve the data compression. The decoding method performs decompression by using the decoding unit aiming at the compression method.

The invention relates to a test data encoding compression method. The test data encoding compression method comprises the following steps of: segmenting original test data by using L as a data section length, wherein L is a positive integer power of 2; if the length of the last data section is less than L bits, then filling X-bits at the tail part of the last data section to complement the residual bits, and obtaining a plurality of data sections; respectively carrying out external compatibility analysis on the plurality of data sections, carrying out backtracking and value assignment on the X-bits in the data sections according to an external compatibility analysis result; carrying out internal compatibility analysis on the data sections without external compatibility to obtain internal encoding types of the data sections and generate corresponding internal reference data sections; and obtaining encoding code words of the data sections according to an encoding rule and the external compatibility analysis result or according to the encoding rule, the external compatibility analysis result, the internal encoding types and the internal reference data sections. The invention has the characteristics of realizing double compression of the test data and improving test data compression ratio.

A method for increasing fault coverage and compression with a broadcast scan-based test data compression circuit includes inserting test points for breaking correlations existing between scan inputs that belong to same scan slices making some faults un-testable with a broadcast scan-based test data compression circuit; and reordering scan inputs for further reducing correlations between scan inputs that belong to the same scan slices.

The invention provides a method for compressing power-number-slit LFSR reseeding VLSI testing data, which is characterized in that: after the testing vector is cascaded, the segmentation is carried out according to the positioning number so that the length of each segment is just the power number of two; furthermore, the positioning number contained by each segment is equal to or less than and mostly approaching to a determinate constant k; subsequently, the compressing is carried out by a linear feedback shift register LFSR. The method is a non-invading data compressing testing method and requires no change of the structure of the circuit to be tested, in particular to the structure of the scanning chain in the circuit; furthermore, memory capacity required for data testing is reduced and the testing application time is shortened.

The method is as the follows. To make statistic for the ratio of 0 and 1 in original test data, all extranous bits are assigned to be 0 and to code as per 0 string if 0 data bits are less then, data bits in the original test data, otherwise to code as per 1 string. Using bit sting as basic unit to divide the said test data for counting length of the bit string code table of adaptive variable length compression method is utilized to convert bit string length into code word to achieve data compression. The decoding method uses decoding unit organized with adaptive variable length compression method to carry on decoding.

A new test data compression method and decompression apparatus is invented for SoC (System-on-a-Chip) architecture. The method is based on analyzing the factors that influence test parameters: compression ratio and hardware overhead. To improve compression ratio, the proposed method is based on Modified Statistical Coding (MSC) and input reduction (IR) scheme, as well as a novel mapping and re-ordering algorithm proposed in a preprocessing step. Unlike previous approaches using the CSR architecture, the inventive method is to compress original test data, but not T_diff, and decompress the compressed test data without the CSR architecture. Therefore, the proposed method leads to better compression ratio with lower hardware overhead than previous works. An experimental comparison on ISCAS '89 benchmark circuits validates the proposed method.

The invention discloses a compression method for test data of an irrational number storage test vector and relates to a fault coverage guided compression method for the test data of the irrational number storage test vector. The compression method comprises the following steps of firstly, generating a fault list according to a circuit structure of an integrated circuit to be tested; secondly, running an automatic test vector generation tool for faults to generate test vectors of corresponding faults; thirdly, counting the lengths of runs; fourthly, performing preliminary estimation on corresponding ranges of irrational numbers; fifthly, dichotomising the ranges of the irrational numbers, and successively approximating; sixthly, filling independent bits; seventhly, performing random test; eighthly, judging whether the fault list in the seventh step is empty or not, if the fault list is empty, turning to the ninth step, and otherwise, turning to the second step; ninthly, ending, and returning all records such as integers m and l corresponding to all the irrational numbers. According to the compression method disclosed by the invention, the coding of the irrational numbers and the generation of the automatic test vectors are combined, so that on one hand, coding numbers, corresponding to the test vectors, of easily-detected fault points are reduced, and on the other hand, the fault coverage is improved.

An architecture and methodology for test data compression using combinational functions to provide serial coupling between consecutive segments of a scan-chain are described. Compressed serial-scan sequences are derived starting from scan state identifying desired Care_In values and using symbolic computations iteratively in order to determine the necessary previous scan-chain state until computed previous scan-chain state matches given known starting scan-chain state. A novel design for a new flip-flop is also presented that allows implementing scan-chains that can be easily started and stopped without requiring an additional control signal. Extensions of the architecture and methodology are discussed to handle unknown (X) values in scan-chains, proper clocking of compressed data into multiple scan-chains, the use of a data-spreading network and the use of a pseudo-random signal generator to feed the segmented scan-chains in order to implement Built In Self Test (BIST).

A method for test data compression includes generating a plurality of test cubes, each test cube comprising test cube data. Each test cube is compared with at least one other test cube, as test cube pairs, to generate a compatibility rating for each compared test cube pair. The compared test cube pair with the highest compatibility rating is determined. The compared test cube pair with the highest compatibility rating is grouped into a test cube set. The remaining test cubes are grouped into test cube sets, as test cube pairs, based on the compatibility ratings of the compared test cube pairs.

For at least one test cube set, a new codeword set is generated. Test cube data is grouped into blocks based on the new codeword set. Compression for the grouped test cube data is computed. A determination is made whether compression is improved as compared to a previous codeword set. If compression is not improved, the test cube set is encoded with the new codeword set to generate an encoded test cube set. If compression is improved, the previous codeword set is set as the new codeword set, and the steps are repeated beginning with generating a new codeword set. The encoded test cube sets are concatenated to form a decompressed encoded test stream. The decompressed encoded test stream is compressed to form a compressed test stream.

Disclosed is a test method for testing a data store having an integrated test data compression circuit where the data store has a memory cell array with a multiplicity of addressable memory cells, read/write amplifiers for reading and writing data to the memory cell via an internal data bus in the data store and a test data compression circuit which compresses test data sequences, which are each read serially from the memory cell array, with stored reference test data sequences in order to produce a respective indicator data item which indicates whether at least one data error has occurred in the test data sequence which has been read.

The invention relates to a building wind tunnel pressure measurement test data compression method. The invention aims at solving the problem that the little attention is paid to frequency domain characteristics of wind load and correlation in the prior art, resulting in a data compression error and an actual application error. The statistical information of the data is reconstructed by the Hermite polynomial, and the spectrum information is reconstructed by the Beta function theory, and a compressed wind pressure filed can be reconstructed at last in combination with random simulation technology. By adoption of the building wind tunnel pressure measurement test data compression method provided by the invention, the building wind tunnel pressure measurement data of GB and TB levels can be compressed to the KB and MB levels, and a novel information extracting and modeling method is provided for the high-dimension time-course large data of the wind load changing with time and space so as to achieve the data compression purpose at last. The building wind tunnel pressure measurement test data compression method is applied to the field of building wind tunnel pressure measurement tests.

A method includes obtaining an equivalent core of multiple cores in a System-on-Chip circuit, and applying linear-feedback shift register LFSR reseeding for compressing test data of the equivalent core.

The invention discloses a test data compression method capable of rapidly searching an irrational number. The test data compression method comprises the following steps of: generating a determined complete test set T and marking the number of test vectors of the complete test set to be N; marking cascading of all test vectors to be S and the length of cascading to be w; calculating the length of runs and ending till reaching an irrelevant position and converting the length information of runs into a decimal x for representing; searching the irrational number and expanding the irrational number to a decimal, wherein the front p items of the decimal are just equal to x, and only integers, namely m, n, l, k and p are stored in the compression process. The test data compression method disclosed by the invention has the advantages that methods of first searching the irrational number and then carrying out bit-by-bit comparison are adopted in the irrelevant bit filling process, and thus the selectivity of the irrational number and the probability of searching the irrational number are increased; and according to the test data compression method, an interval bisection method is adopted in the irrational number searching process, and therefore the operating time can be prolonged according to a logarithm rule.

A multichannel test data compressing and merging method for a distributed real-time test system comprises nine steps of (1) formulating a collecting strategy according to variate features; (2) inquiring newest frame data in a cache, and storing a time label and variate ID (identification) if the ID is the same with a variate value; (3) storing data transmitted from real-time simulated nodes in files by using a master control node; (4) merging and processing information and storing the information in a data structure; (5) traversing data files, and acquiring the variate value from a former frame data to supplement local frame data if only the time label and the variate ID exist; (6) acquiring first frame data of all files, and comparing the first frame data to obtain the frame data with the smallest time label; (7) judging whether the obtained time label is the same with that of the former frame data or not, and writing a line of data to an output file if the obtained time label is different from that of the former frame data; (8) updating the acquired frame data to an id_value_map, and updating changed information so as to bring convenience to next comparison; and (9) repeatedly carrying out the step (6), the step (7) and the step (8) until all files are read, and writing the last line in the output file.

An apparatus, system, and method are disclosed for testing data compression and data encryption circuitry. A pattern configuration module generates initial pattern parameters. Holding registers store the initial pattern parameters. A pattern generation module generates patterns for compression/encryption logic. A detection module detects a failure of the compression/encryption logic. The failure of the compression/encryption logic may be a cyclic redundancy check failure of a decompression module and/or a message authentication code failure of a decryption module.