JP2009180749A - Noise generator, measurement apparatus, and testing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform measurement of two or more noise figures at low cost. <P>SOLUTION: A noise generator, measurement apparatus, and testing apparatus are provided which include a noise source which generates noise signals, a distributor which receives the noise signals, and distributes each of the two or more output signals corresponding to the noise signals to each of the two or more output terminals, and two or more switches which are provided corresponding to the respective two or more output terminals and which are used for choosing whether or not the corresponding output signals are output from the respective output terminals to the outside. A noise generator which provides each of the two or more output signals to two or more devices and each of the two or more devices may also include a measurement part which measures first response signals output when the output signals are not provided and which measures second response signals output when the output signals are provided. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a noise generation device, a measurement device, and a test device.

  Conventionally, a method using a noise source is known as a method for measuring a noise figure of a device. The output of the noise source is input to the device under test, and the output of the device is connected to a measuring instrument such as a spectrum analyzer. The power supply voltage of the noise source is switched on / off, the change in the output noise power density of the measuring instrument is measured, and the noise figure is calculated from a predetermined calculation formula.

  By the way, when such noise measurement is simultaneously performed for a plurality of devices, a noise source and a measuring instrument must be prepared for each of the plurality of devices. However, noise sources are particularly expensive, and it is not practical to prepare the same number as the device under test.

  In order to solve the above-described problem, in the first aspect of the present invention, a noise source that generates a noise signal, a noise signal is received, and a plurality of output signals corresponding to the noise signal are respectively connected to a plurality of output terminals. A noise generator comprising: a distributor for distributing to each of the plurality of switches; and a plurality of switches provided corresponding to each of the plurality of output terminals and switching whether or not to output a corresponding output signal from the corresponding output terminal to the outside. Providing equipment.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

The structure of the measuring device 5 which concerns on this embodiment is shown. The structure of the noise generator 10 which concerns on this embodiment is shown. Operation | movement of the measuring apparatus 5 which concerns on this embodiment is shown. The structure of the test apparatus 40 which concerns on the modification of this embodiment is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 shows a configuration of a measuring apparatus 5 according to this embodiment together with a DUT 100 (Device Under Test). The measuring device 5 measures the noise figure of the DUT 100 such as the entire system in the RF and microwave frequency regions and the components constituting the system such as a preamplifier, a mixer, and an IF amplifier. The measurement device includes a noise generation device 10 and a measurement device 110.

  The noise generator 10 includes a plurality of output terminals 120 and supplies a noise signal to each of the plurality of DUTs 100. The noise generation device 10 includes a distributor that distributes the output of the noise source to each of the plurality of output terminals 120, and a switch that can independently switch on / off of the plurality of outputs. Simultaneously measure the noise figure of the DUT100.

  The measuring apparatus 110 includes a plurality of input terminals 130 and receives output signals of the plurality of DUTs 100. The measuring device 110 measures, for each of the plurality of DUTs 100, a first response signal that is output when no output signal is given and a second response signal that is output when an output signal is given. The measuring apparatus 110 substitutes the measurement result into a predetermined calculation formula to obtain the noise figures of the plurality of DUTs 100, respectively.

  FIG. 2 shows a configuration of the noise generator 10 according to the present embodiment. The noise generator 10 outputs, to each of the plurality of output terminals 120, an off state noise signal when no output signal is applied and an on state noise signal when an output signal is applied. The noise generator 10 includes a noise source 200, a signal distributor 210, an amplifier 220, a variable attenuator 230, a switch 240, and an output terminal 120.

  The noise source 200 generates a noise signal. The noise source 200 includes, for example, a relatively small-capacitance diode that generates noise when a constant current flows and is reverse-biased until avalanche breakdown.

  The noise source 200 outputs avalanche noise in the diode when a reverse bias is applied to the diode. This avalanche noise is called the ON state of the noise source 200, and the noise output value may be expressed as k · Th · B. Here, k represents the Boltzmann constant, and B represents the noise bandwidth of the system. The thermal noise when the reverse bias is zero is called the off state of the noise source 200, and the output value may be expressed as k · Tc · B. The noise output due to the presence or absence of the reverse bias of the noise source 200 may be compared between Th and Tc.

  For example, a value obtained by dividing the difference between Th and Tc by 290 K (Kelvin) and expressed in dB (decibel) is called a decibel format of excess noise ratio (ENR). When the decibel format of the excess noise ratio is ENRdB, the ENRdB of the noise source 200 can be obtained by the following equation.

また、過剰雑音比の線形形式をＥＮＲとすると、ノイズソース２００のＥＮＲは、以下の式で求められる。

Further, assuming that the linear form of the excess noise ratio is ENR, the ENR of the noise source 200 can be obtained by the following equation.

  The signal distributor 210 receives the noise signal of the noise source 200 and distributes each of the plurality of output signals corresponding to the noise signal to each of the plurality of output terminals 120. The signal distributor 210 may be a resistance branching distributor whose impedance is adjusted by electric resistance, or may be a Wilkinson distributor that branches an intended signal frequency by adjusting a transmission line length.

  In the case of equal distribution, the signal distributor 210 ideally has a power value obtained by dividing the input power by the number of distributions as each output value. For example, when the signal distributor 210 is a two-branch equal distributor, the signal distributor 210 ideally outputs a power value that is half of the input power. When the signal distributor 210 is a resistance branching type, the output of the signal distributor 210 is further halved to ¼ of the input power due to the power consumed by the resistor.

  The amplifier 220 amplifies the output of the signal distributor 210. The amplifier 220 amplifies the power value of each noise signal output reduced by being distributed by the signal distributor 210 so that the output at each output terminal 120 becomes the intended power value.

  The variable attenuator 230 adjusts the signal strength of the amplified signal of the amplifier 220 to the intended signal strength. The variable attenuator 230 may be adjusted to adjust the strength of the noise signal according to the noise figure range of the DUT 100 to be measured.

  The switch 240 is provided corresponding to each of the plurality of output terminals 120 and switches whether or not to output a corresponding output signal from the corresponding output terminal 120 to the outside. The switch 240 is switched so as not to output the output signal of the noise source 200 when the noise generator 10 outputs a noise signal in the off state, and is switched so as to output the output signal when outputting the noise signal in the on state. . Here, when the switch 240 is switched off, the switch 240 may ground the output terminal 120 via a termination resistor for impedance matching. Similarly, when the switch 240 is turned off, the switch 240 may be grounded via the terminating resistor so that the reflected signal is not transmitted to the input signal side of the noise source 200.

  Since the noise generator 10 generates a noise signal with the above-described configuration, the respective values of the noise source 200 cannot be used as they are for calculating ENRdB and ENR. For example, the noise signal in the ON state of the noise generator 10 is branched from the noise signal of the noise source 200 by the signal distributor 210, and each output after passing through the amplifier 220, the variable attenuator 230, and the switch 240, respectively. The noise signal is output from the terminal 120. Further, the noise signal in the off state of the noise generator 10 becomes a noise signal output from each output terminal 120 when the switch 240 is turned off. Therefore, ENRdB and ENR of the noise generator 10 calculate Th and Tc corresponding to the noise signal output from the respective output terminals 120 in the on and off states of the noise generator 10, respectively, and then the ENRdB or ENR It is desirable to obtain by substituting into the formula (Formula 1) or Formula (Formula 2) which is a calculation formula.

  FIG. 3 shows the operation of the measuring apparatus 5 according to this embodiment. The measuring device 5 adjusts the intensity of the noise signal used for noise figure measurement by setting the gains of the amplifier 220 and the variable attenuator 230 (S300). Here, the measurement device 5 may set the respective noise signal strengths for each of the plurality of DUTs 100, or may instead set all the noise signal strengths to constant values.

  The measuring device 5 turns off all the plurality of switches 240 and then measures the output signals of the plurality of DUTs 100 using the measuring device 110 (S310). Here, the measuring device 5 stores a plurality of measurement results of the measuring device 110 as Noff (n) (n is a natural number from 1, to the number m of the DUT 100, 1, 2, 3,... M).

  The measuring device 5 turns on all of the plurality of switches 240 and then measures the output signals of the plurality of DUTs 100 using the measuring device 110 (S320). Here, the measuring device 5 stores a plurality of measurement results of the measuring device 110 as Non (n). The measuring device 5 calculates the ratio Non (n) / Noff (n) between the second response signal and the first response signal of the DUT 100 corresponding to the on / off of the noise generating device 10 and then stores it as Y (n). .

  The measuring device 5 calculates the noise figure of each of the plurality of DUTs 100 from a predetermined calculation formula (S330). When the noise figure of the plurality of DUTs 100 is NF (n), a predetermined calculation formula is given as follows.

ここでＥＮＲ（ｎ）はノイズ発生装置１０の複数の出力のそれぞれの過剰雑音比である。またNFmes（ｎ）は、測定装置１１０自身の雑音指数であり、複数のＤＵＴ１００のそれぞれに対応した入力端子１３０から測定装置１１０内部の複数の雑音指数に相当する。

Here, ENR (n) is the excess noise ratio of each of the plurality of outputs of the noise generator 10. NFmes (n) is a noise figure of the measuring apparatus 110 itself, and corresponds to a plurality of noise figures inside the measuring apparatus 110 from the input terminal 130 corresponding to each of the plurality of DUTs 100.

  According to the measurement apparatus 5 of the present embodiment described above, noise figure measurement of a plurality of DUTs 100 can be performed simultaneously with one noise source 200. In the present embodiment, as an example of the noise generator 10, the signal output of one noise source 200 is branched by the signal distributor 210, and each of the plurality of output signals is distributed to each of the plurality of output terminals 120. Alternatively, the respective signal outputs of the plurality of noise sources 200 may be branched using the plurality of signal distributors 210, and the plurality of output signals may be distributed to the plurality of output terminals 120, respectively. .

  In the present embodiment, the procedure for simultaneously performing measurement of a plurality of DUTs 100 has been described as an example of a noise figure measurement method, but instead of this, the measurement apparatus 5 individually performs measurement of each of the plurality of DUTs 100. May be. Although the noise generator 10 has a plurality of noise signal output terminals 120, each noise signal output can be switched on / off independently by a plurality of switches 240. That is, the measuring device 5 can individually execute the noise figure measurement of each of the plurality of DUTs 100 by processing each signal of the measuring device 110 obtained by independently switching the plurality of switches 240. .

  FIG. 4 shows a configuration of a test apparatus 40 according to a modification of the present embodiment. 4, members denoted by the same reference numerals as those in FIG. 1 have substantially the same functions and configurations as those in FIG.

  The test apparatus 40 tests the DUT 100 such as an analog circuit, a digital circuit, a memory, and a system on chip (SOC). The test apparatus 40 inputs a test signal based on a test pattern for testing the DUT 100 to the DUT 100, and determines pass / fail of the DUT 100 based on an output signal output from the DUT 100 according to the test signal. Further, when testing the noise figure of the DUT 100, the test apparatus 40 inputs a noise signal to the DUT 100, calculates the noise figure of the DUT 100 based on the output signal output from the DUT 100 according to the noise signal, and determines pass / fail. . The test apparatus 40 includes the noise generation device 10, a signal generation unit 410, a selection unit 420, and a measurement unit 430.

  The signal generator 410 generates a plurality of test signals to be supplied to the DUT 100. The signal generator 410 supplies a test signal based on the test pattern to the DUT 100 from the plurality of test signal outputs 440.

  The selection unit 420 selects any one of the plurality of test signals output from the signal generation unit 410 and the plurality of noise output signals output from the noise generation device 10 and supplies the selected signals to the DUT 100. The selection unit 420 may select the test signal and the noise output signal with a plurality of changeover switches.

  Measurement unit 430 receives the output signal of DUT 100. When the test apparatus 40 measures the noise figure of the DUT 100, the measurement unit 430 measures the first response signal and the second response signal of the noise generator 10 for each of the plurality of devices.

  When performing the test of the DUT 100, the test apparatus 40 switches the selection unit 420 so that the plurality of test signals output from the signal generation unit 410 are supplied to the plurality of DUTs 100, respectively, and each reception signal of the measurement unit 430 is received. The quality of the plurality of DUTs 100 is determined based on the above. When measuring the noise figure of the DUT 100, the test device 40 switches the selection unit 420 so that the plurality of ON and OFF state noise signals output from the noise generation device 10 are supplied to the plurality of DUTs 100, respectively. Based on the first response signal and the second response signal of 430, the noise figures of the plurality of DUTs 100 are calculated to determine pass / fail.

  Here, the test apparatus 40 can independently perform a test and a noise figure measurement for each of the plurality of DUTs 100. Therefore, the test and the noise figure measurement may be simultaneously performed for each of the plurality of DUTs 100 according to a program intended by the test apparatus 40.

  According to the test apparatus 40 according to the modification of the present embodiment described above, the noise figure measurement and / or test of the plurality of DUTs 100 can be simultaneously performed by at least one noise source 200.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

5 Measuring device 10 Noise generating device, 100 DUT, 110 Measuring device, 120 Output terminal, 130 Input terminal, 200 Noise source, 210 Signal distributor, 220 Amplifier, 230 Variable attenuator, 240 Switch, 40 Test device, 410 Signal generation Section, 420 selection section, 430 measurement section, 440 test signal output

Claims (3)

A noise source that generates a noise signal;
A distributor that receives the noise signal and distributes each of a plurality of output signals according to the noise signal to each of a plurality of output terminals;
A plurality of switches provided corresponding to each of the plurality of output terminals, and a switch for switching whether or not to output a corresponding output signal from the corresponding output terminal to the outside;
A noise generator. The noise generator according to claim 1, wherein each of the plurality of output signals is supplied to a plurality of devices;
For each of the plurality of devices, a measurement unit that measures a first response signal that is output when an output signal is not provided and a second response signal that is output when an output signal is provided;
A measuring device comprising: A test apparatus for testing a device under test,
A signal generator for generating a plurality of test signals to be supplied to the device under test;
A noise generating device according to claim 1;
A selection unit that selects one of the plurality of test signals and the plurality of output signals and supplies the selected signal to the device under test;
A test apparatus comprising:

Images