Abstract: A test device includes: the first reference clock generation unit for generating the first reference clock; the first test rate generation unit for generating the first test rate clock based on the first reference clock; the first driver unit for supplying the first test pattern to an electronic device based on the first test rate clock; the second reference clock generation unit for generating the second reference clock; the first phase synchronization unit for synchronizing the phase of the second reference clock with the phase of the first test rate clock; the second test rate generation unit for generating the second test rate clock based on the second reference clock having the synchronized phase; and the second driver unit for supplying the second test pattern to the electronic device based on the second test rate clock.

Abstract: A semiconductor test device for acquiring a multiplexed clock signal from LSI output data and using the clock to test the LSI. The device includes a time interpolator and registers connected in series. The time interpolator has flip-flops connected in parallel for receiving output data from an LSI under test, a delay circuit for successively inputting strobes delayed at a constant timing interval to the flip-flops and outputting time-series level data, and an encoder for receiving the time-series level data from the flip-flops and encoding it into position data indicating an edge timing. The registers successively store position data from the encoder and output them at a predetermined timing. The device further includes a digital filter for outputting the position data from the registers as a recovery clock.

Abstract: A tester comprising a reference clock generating section for generating a reference clock having a first frequency, a first test rate generating section for generating a first test rate clock having a frequency which is about an integral multiple of the first frequency, a second test rate generating section for generating a second test rate clock having a frequency which is about an integral multiple of the first frequency and different from the frequency of the first test rate clock, a first driver section for supplying a test pattern to an electronic device according to the first test rate clock, and a second deriver section for supplying the test pattern to the electronic device according to the second test rate clock.

Abstract: A test device includes: the first reference clock generation unit for generating the first reference clock; the first test rate generation unit for generating the first test rate clock based on the first reference clock; the first driver unit for supplying the first test pattern to an electronic device based on the first test rate clock; the second reference clock generation unit for generating the second reference clock; the first phase synchronization unit for synchronizing the phase of the second reference clock with the phase of the first test rate clock; the second test rate generation unit for generating the second test rate clock based on the second reference clock having the synchronized phase; and the second driver unit for supplying the second test pattern to the electronic device based on the second test rate clock.

Abstract: A tester comprising a reference clock generating section for generating a reference clock having a first frequency, a first test rate generating section for generating a first test rate clock having a frequency which is about an integral multiple of the first frequency, a second test rate generating section for generating a second test rate clock having a frequency which is about an integral multiple of the first frequency and different from the frequency of the first test rate clock, a first driver section for supplying a test pattern to an electronic device according to the first test rate clock, and a second deriver section for supplying the test pattern to the electronic device according to the second test rate clock.

Abstract: According to the present invention, a variable delay circuit includes a delay circuit unit group, a control unit and an offset delay amount memory group. The delay circuit unit group includes a plurality of delay circuit units, and the plurality of delay circuit units includes two paths having different delay amounts. The offset delay amount memory group includes a plurality of offset delay amount memories, and offset delay amounts corresponding to delay amounts of the first paths of the corresponding delay circuit units are set in the plurality of offset delay amount memories. The control unit includes a plurality of subtracting units, and the plurality of subtracting units select paths of the delay circuit units through which an input signal may pass by using a delay setting value and offset delay amounts. It is possible to reduce volume of the circuit and remove a table since the path is selected by calculation.

Abstract: A timing signal generation circuit comprising: a negative feedback loop comprising; a variable delay circuit for outputting a timing signal delayed from an input clock signal by a delay amount designated by a delay code; a phase difference detector for detecting a phase difference between the timing signal and the input clock signal to output a detection signal; and a loop filter for smoothing a waveform of the detection signal to generate a voltage signal and for feeding the voltage signal back to the variable delay circuit: and a cancel unit for generating a reverse detection signal based on the delay code to cancel the phase difference caused by a change in the delay amount where the reverse detection signal is supplied to the low pass filter.

Abstract: According to the present invention, a variable delay circuit includes a delay circuit unit group, a control unit and an offset delay amount memory group. The delay circuit unit group includes a plurality of delay circuit units, and the plurality of delay circuit units includes two paths having different delay amounts. The offset delay amount memory group includes a plurality of offset delay amount memories, and offset delay amounts corresponding to delay amounts of the first paths of the corresponding delay circuit units are set in the plurality of offset delay amount memories. The control unit includes a plurality of subtracting units, and the plurality of subtracting units select paths of the delay circuit units through which an input signal may pass by using a delay setting value and offset delay amounts. It is possible to reduce volume of the circuit and remove a table since the path is selected by calculation.

Abstract: A timing signal generation circuit comprising: a negative feedback loop comprising; a variable delay circuit for outputting a timing signal delayed against an input clock signal by a delay amount designated by a delay code; a phase difference detector for detecting a phase difference between the timing signal and the input clock signal to output a detection signal; and a loop filter for smoothing a waveform of the detection signal to generate a voltage signal and feed the voltage signal back to the variable delay circuit: and a cancel unit for generating a reverse detection signal based on the delay code to cancel the phase difference caused by a change in delay amount. By the arrangement, a delay amount can be changed with high resolution in operation, while maintaining the phase lock state.

Abstract: The present invention aims to take in an external clock signal generated by a device under test into a semiconductor tester and eliminate jitters involved in the clock signal, thereby stabilizes the clock signal, and to use the clock signal as an operation clock of the tester. Hence, a divider A11 which takes the clock signal 21 generated by the device under test as an input, a phase detector circuit 12, a loop filter 13, a VCO 14 and a divider B16 are provided. In addition, the invention includes a test rate generator 15 and an inter-leave circuit 18. The operation clock which is an output of the VCO 14 is input to the test rate generator 15 to output a test rate signal 23, and distributes the test rate signal to the inside circuits as well as feeds back to the phase detector 12 through the divider B16.

Abstract: The present invention makes possible to generate pulses having set period in high speed. An address series from a pattern generator 11 is converted into two address series, each having two time enabling periods by conversion means 40. A period value memory is read out by these two series of address series. A first and a second fractions read out are stored in flip-flops (FF hereinafter) 41.sub.1 and 41.sub.2 respectively, and integers are stored in FF 43.sub.1 and 43.sub.2 respectively. The output of the FF 41.sub.2 is stored in a FF 46.sub.2. The outputs of the FFs 41.sub.1 and 41.sub.2 are summed and accumulated in an adder 45.sub.1 and the outputs of the FFs 41.sub.1 and 46.sub.2 are summed and accumulated in an adder 45.sub.2. The outputs of the FFs 43.sub.1 and 43.sub.2 are set in coincidence detection counters 62.sub.1 and 62.sub.2 via FFs 58.sub.1 and 58.sub.2 respectively. Each of the counters 62.sub.1 and 62.sub.