JP2011149781A - Test device for rf communication device and method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of performing a test with a burst signal using a modulated signal, and accurately driving an output level into a desired level in a short time and then performing a desired measurement. <P>SOLUTION: A signal generator 10 generates a baseband signal of which level in a cycle Ta shows the same change in any cycle Ta, modulates it with an RF signal and sends the modulated RF signal to the outside. A level measuring part 30 receives a burst signal of a cycle Ta including an On period To and an Off period (Ta-To) from an external communication device, and measures the output level of the burst signal in the On period To of each cycle Ta. A determination part 40 and a level control part 50 control the level of the burst signal to be input to the communication device so that the measured output level is a target value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a test technique for a semiconductor RF communication device used for transmission in, for example, a mobile communication terminal. In particular, an RF communication device, for example, an amplifier, transmits a burst signal obtained by bursting a modulation signal obtained by modulating a baseband signal with an RF signal. The present invention uses the burst signal, and the RF communication device outputs the burst signal. The present invention relates to a test technique for a device for RF communication in which a desired test can be performed after the output level of a burst signal is quickly driven to a target range.

  Conventionally, SG (signal generator), spectrum analyzer, level meter, network analyzer, etc. are often used for testing (evaluation) of RF-related semiconductor devices. The signals handled by these are basically CW. However, in recent years, digital mobile radio has increased and digital modulation signals have increased as signals handled by these. Therefore, it is desired to use a digital modulation signal even in a test (evaluation) of a semiconductor device.

  An example of the digital modulation signal is a time for turning on a certain period (time when the modulation signal exists; hereinafter referred to as “on section”) and a time for turning it off (time when no signal exists; hereinafter, “off” The level (amplitude) at the time when the signal is turned on changes with time. When such a burst signal is used as a test signal, the value changes depending on which waveform part is measured at what point in time, even if “signal level measurement” is used. In many cases, a long-term level exceeding 1 mm was measured, and the averaged process obtained a stable measurement result for evaluation.

  For example, in the technique described in Patent Document 1, it is described that when a burst signal is used, the level is measured in synchronization between the transmission side and the reception side. The RF signal existing in the ON section is not a modulation signal but a CW signal.

  On the other hand, test items for RF communication devices, such as amplification semiconductor devices, include EVM characteristics, adjacent channel leakage power characteristics, harmonic distortion characteristics, and the like, which are characteristics that affect communication quality. Furthermore, there is a power consumption characteristic as a characteristic that affects the battery life of a portable mobile communication terminal.

  In order to test each of these characteristics, it is necessary to test the RF communication device under a certain condition in order to perform comparison such as comparison of differences between individual RF communication devices to be tested, pass / fail judgment, and the like. It is desired. In general, it is well known that a device for RF communication has a linear region and a nonlinear region. However, in each test, it can be obtained as a result of the test whether the operating point belongs. There is a big difference in the characteristics to be obtained.

  Therefore, it is desired that the test is performed under the condition that the output level of the RF communication device is driven to a desired level as an operation condition at least for each test item as the fixed condition. In addition, the variation in the test result may be expanded due to the variation in the controlled output level, so that it is necessary to control with high accuracy. One example is current consumption characteristics. As the operating point moves from the linear region to the non-linear region, the current consumption tends to flow rapidly, and thus the variation in the current consumption characteristic tends to increase beyond the variation in the output point level.

  Thus, in order to control the output level of the device for RF communication to a desired level, it is indispensable to measure the output level, and the measurement is performed for a long time as measured by CW as described above. An average value was obtained and measured.

            JP 2006-242624 A

  On the other hand, in the mobile communication terminal market today, production volume is increasing, competition is intensifying, and costs are decreasing. As a result, manufacturers face challenges such as lower device costs, improved yield rates, and mass production.

  Among these problems, one of the problems to be answered as a tester is to shorten the test time and improve the yield rate. In particular, as described above, the output level of the RF communication device is driven to a desired level with high accuracy, and the test is performed. However, the test using the CW as described above is different from the actual operation using the modulation signal. Even if measurement is performed with a burst signal of a modulation signal close to actual operation, it takes too much time to accurately drive the output level to a desired level in level measurement based on long-time averaging.

Furthermore, some users may wish to generate the burst signal on the user side for the convenience of the device. In this case, the level of the burst signal may change for each period Ta of the burst signal, and the level measurement timing and the period of the burst signal must be measured asynchronously.

  Therefore, the present invention provides a test apparatus and method for enabling a test with a burst signal using a modulation signal, driving the output level to a desired level with high accuracy in a short time, and performing desired measurement thereafter.

  In order to achieve the above object, the present invention generates a baseband signal, modulates it with an RF signal, and sends the modulated RF signal to an external (user-side) communication device. Then, the output level in the on section To of the burst signal having the cycle Ta composed of the on section To and the off section (Ta-To) sent from the external communication device is measured. At that time, the amplitude (level) of the baseband signal in the period Ta is set so that the level to be measured for each period Ta does not change even if the ON section To is set and burst at any time position of the modulated RF signal. The change is made the same for every period Ta. Further, the burst signal level input to the communication device is controlled so that the measured output level becomes a target value (target level).

Specifically, in order to achieve the above object, the invention according to claim 1 outputs a modulation signal obtained by modulating a baseband signal with an RF signal to the outside, and externally outputs the modulation signal within a period Ta. An RF communication device test apparatus for inputting a burst signal generated so as to be included in To to an RF communication device, receiving the output of the RF communication device, and testing the RF communication device, and having a period Ta And a baseband signal having a level that changes with time in each period Ta is the same in any period Ta, and the baseband signal is generated by the RF signal. In response to the output from the signal generating unit (10) for outputting the modulated modulation signal to the outside and the external RF communication device, the front is synchronized with the period Ta. The level measurement unit (30) that measures the output level in the section To, the determination unit (40) that compares the output level measured by the level measurement unit with a preset target value, and the determination unit are measured. When it is determined that the output level is outside the target value, a level control unit (50) that controls the level of the burst signal output from the signal generation unit so that there is no difference between the measured output level and the target value. ), And after the determination unit determines that the measured output level is within a target value, the test is performed.
According to a second aspect of the present invention, in the first aspect of the invention, the level measuring unit integrates the interval To and measures the output level.
The invention according to claim 3 is the invention according to claim 1 or 2, wherein the level control unit sets a control amount for controlling the level of the burst signal to the signal generation unit for each period Ta. The signal generator is controlled by sending a reflected gain control signal, and based on the gain control signal sent in the previous cycle Ta and the comparison result of the judgment unit at that time, the signal generator is eliminated. And a control amount estimating means (51) for estimating a new control amount to be controlled and sending the gain control signal reflecting the new control amount to the signal generator.
According to a fourth aspect of the present invention, in the third aspect of the present invention, the control amount estimating means holds in advance characteristic information indicating the control amount of the RF communication device versus the output level. Thus, the control amount is estimated by referring to the characteristic information based on the determination result from the determination unit and the level setting means based on the gain control signal in the previous cycle Ta.
The invention according to claim 5 is the invention according to claim 3 or 4, wherein the level control unit determines in advance that the output level measured by the determination unit during a past test is within a target value. The control amount estimation means has an initial control amount management means (52) for managing the past control amount reflected in the gain control signal, and the control amount estimation means, when starting the control, The gain control signal reflecting the past control amount is sent to the signal generation unit, and the gain control signal reflecting the past control amount is transmitted to the gain control in the previous cycle Ta in the next cycle Ta. The signal is configured to estimate the next control amount.
The invention according to claim 6 has the operation unit (61) and the display unit (62) in the invention according to any one of claims 1 to 5, wherein the determination unit is configured to include the target. A representative test result distribution characteristic indicating a distribution of the test result with respect to a change in value is stored, and before the start of the test, the test result distribution characteristic is stored as a target value of the test result distribution characteristic or the test. Any one of the distributions of the results is displayed on the display unit so that it can be specified by the operation unit, and when the target value is specified on the test result distribution characteristic, the target level of the specified value, or A configuration in which when the result of the test is designated, a target value corresponding to the designated test result is set from the representative distribution characteristic for comparison with the output level measured by the level measuring unit; did.
The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the target value includes an allowable level range and a specific level within the allowable level range, and the determination unit includes The level measurement unit compares the output level measured by the level measurement unit with the specific level, and the level control unit determines that the output level measured by the determination unit is outside a target value. The level of the burst signal output from the signal generation unit is controlled so that the level difference between the output level measured in step 1 and the specific level is eliminated, and the output level measured by the determination unit in the level measurement unit is When it is determined that the level is within the allowable level range, the burst signal level at that time is maintained.
The invention according to claim 8 outputs a modulated signal obtained by modulating a baseband signal with an RF signal to the outside, and a burst signal generated so as to include the modulated signal in the section To within the period Ta is RF. A device test method for RF communication, which is input to a communication device and receives the output of the RF communication device to test the RF communication device, comprising: a baseband signal having a period Ta; The baseband signal whose level changing with time in the period Ta changes the same in any period Ta is generated, and the modulation signal obtained by modulating the baseband signal with the RF signal is output to the outside. A level measurement that receives a signal generation stage and an output from the external RF communication device and measures an output level in the section To in synchronization with the period Ta. A step of comparing the output level measured by the level measurement unit with a preset target value, and the measurement when the determination unit determines that the measured output level is outside the target value A level control stage for controlling the level of the burst signal output from the signal generator so that the difference between the output level and the target value is eliminated, and the output level measured by the determination unit is within the target value. A test stage for performing the test after the determination, and

  According to the present invention, since a test can be performed using a burst signal using a modulation signal, a test close to actual operation is possible.

  Even when bursting is performed on the user side, an RF signal indicating the same change in the amplitude of the burst signal within each period Ta is sent to the user side, and the output of the RF communication device is output at any timing on the user side. When the level is measured, the level to be measured for each cycle Ta is the same, so the output level can be measured for each cycle Ta. That is, level measurement is possible in a short time.

  Moreover, since the measured output level is compared with the target value (level), the result is fed back, and the level of the burst signal input to the RF communication device is controlled so that they match, Drive to the target value with high accuracy. In addition, since the control can be performed every cycle Ta, it can be driven in a short time.

It is a figure which shows the function and structure of embodiment of this invention. It is a figure which shows the detailed function and structure of the signal generation part of FIG. FIG. 3 is a diagram mainly illustrating each signal of a signal generation unit in FIG. 2. FIG. 2 is a diagram illustrating a detailed function and configuration of a determination unit in FIG. 1 and explaining it. It is a figure which shows the detailed function and structure of the level control part of FIG. It is a figure for demonstrating operation | movement of the structure of FIG. It is a figure which shows a series of operation | movement flows of this invention.

  Embodiments according to the present invention will be described with reference to the drawings. FIG. 1 shows an external configuration 80 including a DUT (RF communication device) 80a to be tested, and a function / configuration of a test apparatus 100 that tests the external configuration 80.

  1 includes a clock generation unit 11, a baseband signal generation unit 12, an RF modulation unit 13, and a variable gain unit 14, and generates an RF signal obtained by modulating a baseband signal having a period Ta.

  In FIG. 2, the clock generation means 11 is necessary for the read control means 12b of the baseband signal generation means 12 to read out digital data (referred to as “symbol data”) from the waveform data storage means 12a to form baseband data. A simple clock is generated (see the timing diagrams of FIGS. 3A and 3B).

  1 and 2, the read control unit 12b reads the digital data in the period Ta from the waveform data storage unit 12a in response to the clock from the clock generation unit 11, and converts the read digital data into D / A. The conversion means 12 c performs digital-analog conversion to form a baseband signal and sends it to the RF modulation means 13.

  Specifically, the read control means 12b in FIG. 2 has a counter (or timer), receives a clock signal from the clock generation means 11 shown in FIG. Digital data is repeatedly read from the storage means 12a over a period Ta and every period Ta.

  At that time, the reading control means 12b is in the same address h to h + n-1 of the waveform data storage means 12a in any cycle Ta (n is the number of data filling the cycle Ta, that is, between the cycles Ta The digital data is read by accessing (the number of addresses corresponding to the number of data necessary for the digital data to be continuously present). By doing so, the amplitude of each read digital data changes over a time Ta (corresponding to a cycle) for reading the digital data at addresses h to h + n−1 (n), but at any cycle Ta. The same change. In addition, since the digital data continuously exists during the period Ta, the digital data exists without interruption even at the change of the period Ta. Even if it is later RF-modulated and converted to a burst signal in the external configuration 80, it shows relatively the same amplitude change in each period Ta, and the RF signal is present without interruption.

  Of course, the waveform data storage means 12a stores digital data of the number of digital data that will be read during the period Ta. Then, when it becomes a burst signal later, as shown in FIG. 3 (d), only digital data in a time corresponding to the on period To is used.

  Furthermore, as numerical examples, the cycle Ta = 5 ms, 4.615 ms (in the case of GSM / EDGE), and the like.

  1 and 2, the mixer 13a performs RF modulation by mixing the baseband signal received from the baseband signal generator 12 with the RF signal output from the local signal generator 13b. The modulated modulation signal is sent to the variable gain means 14.

  The variable gain means 14 is generally composed of a variable gain amplifier or a variable attenuation element (circuit), and the amplitude (level) of the modulation signal received from the RF modulation means 13 is changed to a gain control signal from the level control section 50. Variable according to b and sent to the burst means 80b of the external configuration 80.

  The variable gain means 14 in FIGS. 1 and 2 functions between the RF modulation means 13 and the burst means 15, but functions between the baseband signal generation means 12 and the RF modulation means 13. It may be configured. However, when the variable gain means 14 is located after the RF modulation means 13, it is necessary to have a frequency characteristic that responds to the RF signal, and when it is between the baseband signal generation means 12 and the RF modulation means 13. Any frequency characteristic that responds to the baseband signal is sufficient.

  The external configuration 80 includes burst means 80b and a DUT 80a to be tested. The burst means 80b receives a burst timing signal a having a period Ta having an on period To and an off period (Ta-To) and gates the RF signal so that the RF signal exists in the period Ta. On-period To and a burst signal c having an off-period (Ta-To) in which no RF signal is passed are generated and sent to the DUT 80a. The DUT 80 a amplifies the input burst signal c and sends it to the level measurement unit 30.

  The level measurement unit 30 measures the output level of the burst signal c ′ output from the DUT 80a. When the DUT 80a is an amplifier, an amplified burst signal is output. At this time, the level measurement unit 30 samples the modulated RF signal existing during the on interval To of the received burst signal c ′ and extracts the level as a level measurement target (see FIGS. 3D and 3E). (Refer to Fig. 4), integrate it with an integration means, or detect an average value, and output it as a measured value of the output level of DUT 80a (the level of burst signal c ').

  In order to extract the level measurement target signal in the on section To, extraction is performed based on the start timing and end timing of the on section To. At that time, the level measuring unit 30 compares the burst signal received from the DUT 80a with a predetermined threshold, and when the burst signal becomes equal to or higher than the predetermined threshold, the start timing is set, and the level is below the predetermined threshold. The end timing is defined as the time when is detected. Then, the level between the start timing and the end timing is measured and output as a measured value.

  The measurement value measured by the level measurement unit 30 is measured asynchronously with the burst timing in the external configuration 80, but can be obtained at any period Ta regardless of the period Ta. Even if the burst timing in the external configuration 80 deviates from the period Ta of the baseband signal or the like as shown in FIG. 3D (Example 1), or as shown in FIG. 3E (Example 2). Even in the form of straddling the period Ta of the baseband signal, as described above, the baseband signal has relatively the same amplitude change in each period Ta, and the baseband signal exists without interruption in each period Ta. Therefore, the measured value for each period Ta is the same.

  The level measurement unit 30 may be an average value as long as the target value, which is a reference when the determination unit 40 described later, determines a target value that corresponds to the average value in the section To. In short, the unit is set so that the target value and the measured value are to be compared.

The determination unit 40 sends to the comparison unit 42 an allowable range that is a desired level range that the target level management unit 41 has in advance and a target value that has one point within the allowable range as a specific level value. The comparison means 42 compares the output level measurement value of the DUT 80a sent from the level measurement unit 30 with the allowable range and the specific level value, and outputs the following determination result d of (i) and (ii).
(I) If the measured value is not within the allowable range, the difference value between the specific level value and the measured value is output as the determination result d.
(Ii) If the measured value is within the allowable range, a signal indicating OK and a difference value between the specific level value and the measured value are output as the determination result d.

  The target level management unit 41 can selectively set the allowable range and the specific level value in accordance with the inspection item by the measurement unit 20. Furthermore, it is possible to adopt a configuration in which the allowable range and the specific level value can be selectively set in consideration of variations in the inspection results of the inspection items.

  In particular, since the inspection of the DUT 80a by the measuring unit 20 is performed on condition that the output level of the DUT 80a is set to a desired target value, the inspection result may vary depending on the target value. An example is shown in FIG. FIG. 4B is a past measurement example. For test item A, when the output level of DUT 80a is set to each of specific levels AL1, AL2, and AL3, allowable range (AW) versus test result It is a figure which shows variation ((sigma)). In general, if the specific level is a linear region of DUT 80a, the characteristics shown in FIG. 4B are close to a single characteristic even if the specific levels are AL1, AL2, and AL3. In the non-linear region, there is a high possibility that they will have different characteristics. In the example of FIG. 4B, it is shown that the allowable range needs to be changed to AW1, AW2, and AW3 according to the specific level AL in order to enter the same variation range σA.

  Therefore, the target level management means 41 is more preferably configured as follows. An example of the target level management means 41 will be described with reference to FIG.

  In FIG. 4 (A), the test result distribution characteristic storage unit 41a has a characteristic (hereinafter referred to as the relationship between the tolerance (test result distribution) and the variation of the test result in advance in the past inspection as shown in FIG. 4 (B). This is referred to as “test result distribution characteristic”. Then, the characteristic display data generation unit 41c reads the test result distribution characteristic from the test result distribution characteristic storage unit 41a, generates a graph as shown in FIG. 4B, and displays it on the display unit 62. Then, at the start of the test (before the main test such as the test of the current consumption characteristic, at the start of driving for driving the output level of the DUT 80a to the target value; hereinafter referred to as “at the start of testing”. The start of the main test such as the characteristic test is referred to as “main test start”.) When the specific level AL, the variation σ of the test result, and / or the allowable range are set from the operation unit 61, The value is also displayed. By doing so, for example, when AL2 and variation σA are specified as the specific level by the operator, the allowable range setting means 41b refers to the test result distribution characteristic storage unit 41a to determine the allowable range AW2. At this time, the characteristic display data generating unit 41c displays the values AL2, σA, and AW2 on the graph of the display unit 62 so that they can be identified. The permissible range setting means 41b having received that the operator who has seen it has issued an OK instruction sets AL2 ± [AW2 / 2] (specific level ± allowable range / 2) as a target value in the comparison means. . In addition to the [specific level ± allowable range / 2] form (hereinafter described in this form), the method of setting the target value is [absolute value ALX (= AL2- [AW2 / 2]). ~ Absolute value ALZ (= AL2 + [AW2 / 2]) (in this case, the specific level is automatically set to (ALX + ALZ) / 2) or [absolute value ALX ~ (absolute value ALX + allowable range)] There is a way of setting.

  When the operator designates the specific level AL2 and the allowable range AW2 as the target values, the allowable range setting unit 41b refers to the test result distribution characteristic storage unit 41a to obtain the variation σA, and displays the characteristic display data. Through the generating means 41c, the values AL2, AW2, and σA are displayed on the graph of the display unit 62 so as to be distinguishable. It is better if the allowable range setting means 41b can set AL2 ± [AW2 / 2] as the target value in the comparison means 42 when the operator gives an OK (confirmation) instruction from the operation unit 61.

  By adopting the configuration of the target level management means 41 of FIG. 4 as described above, the operator can set the target value in consideration of variations in the specific level, the allowable range, and the test result.

  The level control unit 50 receives the determination result d from the determination unit 40, and causes the variable gain means 14 to vary the level of the burst signal so that the measured value of the output level of the DUT 80a falls within the allowable range, whereby the DUT 80a Is a means for driving the output level (the level of the burst signal c ′ and the measured value of the level measuring unit 30) into the allowable range of the target value. The level control unit 50 controls the variable gain means 14 by sending a gain control signal b reflecting a control amount for changing the level. In the following description, the control amount will be mainly described.

  The level control unit 50 mainly has a configuration for performing the following operations (A) to (C). (A) relates to a method of setting an initial control amount of the driving, (B) relates to a method of estimating a control amount in the subsequent driving control, and (C) relates to an operation at the time of driving.

(A) Initial setting at the start of test; start-up control start At the start of the test, the initial control amount management means 52 stores and manages one of the following initial values, and the variable gain means 14 via the control amount estimation means 51 Set to.
(A-1) Initial values corresponding to test items are stored in advance in the initial control amount management means 52 of FIG. 1, and initial values corresponding to the test items are set.
(B-2) Description will be made based on the details of the initial control amount management means 52 of FIG. 5 (in this case, the operation is different from the above (e1)). When the lot data storage unit 52a of the initial control amount management unit 52 in FIG. 5 has previously measured the output level of the DUT 80a within the allowable range as a result of the test in the past lot for each test item, An average value of control amounts when the control amount estimating means 51 (setting means 51c) controls the variable gain means 14 is stored (see FIG. 6B). The average value is calculated by the average value calculation means 52b. Then, the average value corresponding to the test item is set in the variable gain means 14 at the start of the test via the setting means 51c. At this time, the average value of all the lots may be used, or the designation of the corresponding lot number may be received from the operation unit 61, and the average value of the corresponding lot may be used. For example, when the test is completed for up to five lots and the sixth lot is tested, an average value up to the fifth lot may be set.

(B) Control when the determination result d by the determination unit 40 is (i) above: Drive-up control The control amount estimation means 51 of the level control unit 50 determines that the determination unit 40 does not fall within the allowable range. In this case, only the difference value between the specific level value and the measured value is received as the determination result d, the next control amount is estimated, and the variable gain means 14 is controlled with the estimated control amount. In this case, there are the following examples, and either of them can be adopted.
(B-1) The reference management means 51a of the control amount estimation means 51 is previously set in FIG.
As shown in FIG. 5, a representative characteristic (hereinafter referred to as “representative characteristic”) of the output level characteristic of the control amount corresponding to the test item versus the DUT 80a is stored. Then, the setting means 51c sets the average value of past lots (which may be the initial value in (A-1)) as the initial control amount as described in (A-2) at the beginning of the test. Next, the following steps are executed. (Step 1) The determination unit 40 determines the level difference ΔL (see FIG. 6C) between the initial measurement value at which the level measurement unit 30 measures the output level of the DUT 80a and the specific level at the target value. d is sent to the setting means 51c. (Step 2) The setting means 51c moves the representative characteristic so as to match the initial control amount and the initial measurement value (estimated characteristic indicated by the dotted line in FIG. 6C). (Step 3) The setting means 51c determines the next control amount corresponding to canceling the calculated level difference ΔL on the moved representative characteristic (estimated characteristic) in FIG. This is sent to the variable gain means 14 for control. Thereafter, the operations of steps 1, 2, and 3 are repeated until the determination unit 40 determines that the measurement value by the level measurement unit 30 is within the allowable range of the target value.
(B-2) The above (B-1) has typical characteristics in advance, and the next control amount is estimated based on the typical characteristics. The typical characteristics can be expressed by polynomials, and inflection points. It is known that a smooth curve with no point can be estimated with three points. Therefore, for example, the setting unit 51c stores the measurement values ML1, ML2, and ML3 obtained by the level measurement unit 30 when measured with the control amounts of SL1, SL2, and SL3 in the control amount storage unit 51b, and these three control amounts are stored. Based on this, the representative characteristic is estimated (calculated), and the control amount SL4 that should cancel the level difference [ML3-specific level] between the specific level of the target value and the measured value ML3 is estimated from the estimated representative characteristic ( Calculation) to set and measure to obtain the measured value ML4. When the measured value ML4 is not within the allowable range, the representative characteristics are estimated based on the measured values ML2, ML3, and ML4 when measured with the control amounts SL2, SL3, and SL4, and the estimated representative characteristics are The control amount SL5 that should be canceled out is the level difference [ML4-specific level] between the specific level of the target value and the measured value ML4. Hereinafter, the determination unit 40 repeats until OK is obtained.
(B-3) The above (B-1) and (B-2) are representative characteristics approximated by polynomials, and the control amount is estimated. However, in the narrow range of the control range, or the narrower the line, Approximate approximation is possible. In that case, the typical characteristic approximated by the polynomial in (b-2) above can be approximated by a straight line. In other words, instead of estimating the control amount with the nearest three control amounts and three measured values in (b-2) above, a linear representative from the two nearest control amounts and two measured values. The next controlled variable can be estimated by approximating the target characteristics.

(C) Control in the case where the determination result by the determination unit 40 is (ii) above; end of the follow-up control The measurement value by the level measurement unit 30 is shown in the figure by the control and operation for each period Ta in (b) and (b) above. 6 (D) approaches the target value, and the determination unit 40 outputs a signal indicating that the measured value is within the allowable range and indicating OK and the difference value between the specific level value and the measured value as the determination result d. Upon receiving this, the setting means 51c in FIG. 5 maintains the control amount that was controlling the variable gain means 14 at that time (stops updating of the control amount), and maintains the control amount via the control amount storage means 51b. The control amount is sent to the lot data storage means 52a and recorded on the corresponding lot number of the corresponding lot (see FIG. 6B). Then, the average value calculating means 52b obtains an average value based on the control amount previously recorded in the same lot and the control amount recorded this time, and stores it in the lot data storage means 52a. By doing so, it can be used as in (b-2) above. As described in (E1) above, when the control is always started with the initial value stored in advance, it is not necessary to store lot data, calculate an average value, or the like.
Furthermore, the setting unit 51c notifies the control unit 70 that the determination unit 40 has issued an OK. That is, it is notified that the follow-up control is completed and the output level of the DUT 80a is maintained at the target value.

After receiving the signal indicating the OK, the control unit 70 controls the measurement unit 20 to start the main test of the DUT 80a for a desired test item. For example, test items include power consumption characteristics, EVM characteristics, adjacent channel leakage power characteristics, harmonic distortion characteristics, and the like. The measurement unit 20 includes a measurement device, an ammeter, a spectrum analyzer, and the like for testing these test items. Further, the measurement unit 20 may include a signal generator that also serves as the signal generation unit 10 so that the frequency of the local signal generation unit 13b can be changed.
Furthermore, the measurement unit 20 is a signal analysis device that also has a level measurement unit 30 and is configured to measure a level and measure an EVM characteristic, an adjacent channel leakage power characteristic, a harmonic distortion characteristic, and the like. Also good.

  When one test item is completed, the control unit 70 instructs the level control unit 50 to control the next test item so that the output level of the DUT 80a falls within the target value. Even if the test items are different, if the output level of the DUT 80a is the same, it is not necessary to control again, and different test items are tested.

  Next, a series of operations will be described with reference to FIG. Here, an example in which the operator designates the specific level AL2 and the allowable range AW2 as target values will be described.

  Step S00: After the power is turned on, the user interface 60 displays a guidance screen on the display unit 62 for various test items such as power consumption characteristics, EVM characteristics, adjacent channel leakage power characteristics, and harmonic distortion characteristics, and the DUT 80a. Guide the exam. The operator designates the desired test item by selecting it with the operation unit 61 according to the guide.

  Step S01; Next, the target level management means 41 displays the test result distribution characteristic at the time of the past examination stored in advance relating to the designated test item as a graph as shown in FIG. To display. Then, the operator sets a target value; AL2 ± [AW2 / 2] (specific level ± allowable range / 2) in consideration of the variation σ of the test result using the operation unit 61. The target value can also be set directly without displaying the above graph and considering the variation σ.

  Step S02; Further, as described in (E2) above (when (E2) is adopted), the level control unit 50 previously determines that the measured value of the output level of the DUT 80a is within the allowable range in the past test. When the control amount estimation means 51 (setting means 51c) controls the variable gain means 14, the average value of the control amounts is stored for each lot. When the level control unit 50 receives the designation of the corresponding lot number from the operation unit 61 by the operator as the initial control amount setting, the level control unit 50 sets the average value of the control amount to the corresponding test item of the corresponding lot. In addition, the variable gain means 14 variably controls the level of the burst signal so that the measured value of the output level of the DUT 80a falls within an allowable range. That is, the follow-up control is started as described in (b) above.

  Step S1; On the other hand, the signal generator 10 generates a baseband signal having a period Ta, and a baseband signal whose amplitude changing with time in each period Ta changes the same in any period Ta. Generated and modulated signal obtained by modulating the baseband signal with the RF signal is output to the external configuration 80.

  Step S2: At that time, the signal generator 10 causes the variable gain means 14 to change the RF signal to the initial control amount indicated by the gain control signal b from the level controller 50 at the initial time (at the start of the tracking control). Output to the external configuration 80 at the corresponding level. Thereafter, the variable gain unit 14 changes the level of the RF signal to a level corresponding to the control amount instructed from the level control unit 50 based on the determination result d of the determination unit 40 and outputs the level to the external configuration 80.

  External configuration step (operation executed on the user side): The RF signal is gated (made into a burst) in the period Ta and the on period To in the external (user side), and the burst signal is output to the DUT 80a. The DUT 80a amplifies the burst signal and sends it to the level measuring unit 30.

  Step S3: The level measuring unit 30 receives the burst signal c ′ output from the DUT 80a and measures the output level. An average value is obtained by integrating signals in the ON section Ta of the burst signal c ′ output from the DUT 80a as a measurement value.

  Step S4: The determination unit 40 determines whether or not the output level measurement value measured by the level measurement unit 30 is within the set target value. Specifically, it is determined whether or not the output level is within the range of the target value; AL2 ± [AW2 / 2]. When the determination unit 4 determines that the output level is outside the target value range, the determination unit 4 sends the level difference [output level−AL2] and the specific level AL2 to the level control unit 50 as determination results. When it is determined that the measured value is within the target value range, “OK” and the level difference [output level−AL2] are sent to the level control unit 50 as a determination result.

  Step S5: The level control unit 50 receives the level difference ΔL = [output level−AL2] and the specific level AL2 as the determination result d by the determination unit 40, and performs the follow-up control. That is, in the method described in (Row 1), the setting unit 51c stores the reference control unit 51a based on the initial control amount set in Step S02 and the output level measurement value measured by the level measurement unit 30. The representative characteristic that has been set is moved (estimated characteristic indicated by a dotted line in FIG. 6C) so that the initial control amount corresponds to the measured value. Further, the setting means 51c determines the next control amount corresponding to canceling the level difference ΔL = [output level−AL2] on the moved representative characteristic (estimated characteristic) in FIG. This is sent to the variable gain means 14 for control. Thereafter, in step S4, the above-described control operation of steps S2 to S5 is repeated until the determination unit 40 determines that the measurement value by the level measurement unit 30 is within the allowable range of the target value.

  Step S6: The level control unit 50 repeats the operations of Steps S2 to S5 described above, and receives “OK” and the level difference [output level−AL2] as the determination result d from the determination unit 40. That is, as described in the above step S5, as a result of repeating the follow-up control operation in steps S2 to S5 for each cycle Ta, the measured value by the level measuring unit 30 approaches the target value, and the setting means 51c of the level control unit 50 Receives “OK” and the level difference [output level−AL2] as the determination result d from the determination unit 40. The setting means 51c maintains the control amount that was controlling the variable gain means 14 at that time and stops updating, and the maintained control amount and the level difference [output level−AL2] are stored in the lot data storage means 52a. (Note that the level difference [output level−AL2] may be used for reference later, so it is only stored). Then, the average value calculating means 52b obtains an average value based on the control amount previously recorded in the same lot and the control amount recorded this time, and stores it in the lot data storage means 52a. By doing so, it can be used for setting the initial control amount in step S02 in the next test.

  Then, in a state where the output level of the DUT 80a is maintained within the target value, the control unit 70 controls the measurement unit 20 for the measurement item selected and set in step 00, and performs the test for the designated measurement item. Execute.

[About the period of the modulation signal of the signal generator 10 and the period Ta of the burst timing signal a of the external configuration 80]
In the description of the above configuration and the series of operations in FIG. 7, the period Ta for generating the modulation signal in the signal generator 10 and the period Ta of the burst timing signal a have been described as being the same. Specific examples of the method of setting both of them to the period Ta include the following methods i) and ii). If any of these configurations and operations is included in the operation of step S1 in FIG. good. Although it is desirable that the period Ta is the same, the two need not be in a temporal synchronization relationship.
i) The operator sets the same period Ta as the period Ta of the burst timing signal a of the external configuration 80 in the signal generation unit 10, and the signal generation unit 10 (particularly the baseband signal generation unit 12) is based on the clock signal. Timing of cycle Ta / n (n: number of digital data read during cycle Ta) is generated.
ii) The period Ta of the burst timing signal a of the external configuration 80 is measured by the test apparatus 100 and set in the signal generator 10 (then, the same operation as i) is performed thereafter). In this case, as shown by the dotted line in FIG. The burst period measuring means 31 detects the signal in the ON section To of the burst signal c ′ and counts the timing of the detection output (if the average is detected when measuring the level, the output may be used). Measure the period. The overall operation is as follows.

  That is, an arbitrary initial period Tx is set in the signal generation unit 10, and the signal generation unit 10 outputs a modulation signal modulated in the initial period Tx to the external configuration 80. The modulated signal is burst-modulated with a period Ta by the burst timing signal a, and is input from the DUT 80 to the burst period measuring means 31 as a burst signal c ′. The burst period measuring unit 31 measures the burst period Ta of the burst signal c ′ and notifies the signal generation unit 10 via the control unit 70. The signal generator 10 operates in the notified burst cycle Ta instead of the previously set initial cycle Tx, and outputs a modulation signal of the cycle Ta.

  The determination unit 40, the level control unit 50, and the control unit 70 in the configuration of FIG. 1 can be configured by a program describing the operation flow in FIG. 7 and a CPU that executes the program.

10 signal generator,
11 Clock generation means,
12 baseband signal generation means, 12a waveform data storage means,
12b read control means, 12c D / A conversion means,
13 RF modulation means, 13a mixer, 13b local signal generation means,
14 variable gain means,
20 measuring section,
30 level measurement unit, 31 burst period measurement means,
40 determination unit,
41 target level management means, 41a test result distribution characteristic storage unit,
41b allowable range setting means, 41c characteristic display data generation means,
42 comparison means,
50 level controller,
51 control amount estimation means, 51a reference management means, 51b control amount storage means, 51c setting means,
52 initial control amount management means, 52a lot data storage means,
52b Mean value calculating means,
60 user interface,
61 operation unit, 62 display unit,
70 control unit,
80 External configuration,
80a DUT (device for RF communication), 80b burst means,
100 test equipment

Claims (8)

A modulation signal obtained by modulating a baseband signal with an RF signal is output to the outside, and a burst signal generated so as to include the modulation signal in the interval To within the period Ta is input to the RF communication device, An RF communication device test apparatus for receiving an output from a communication device and testing the RF communication device,
A baseband signal having a period Ta, and the baseband signal having a level that changes with time in each period Ta is the same in any period Ta, and the baseband signal is generated as the RF signal. A signal generator (10) for outputting the modulated signal modulated by a signal to the outside;
A level measuring unit (30) that receives an output from the external RF communication device and measures an output level in the section To in synchronization with the period Ta;
A determination unit (40) for comparing the output level measured by the level measurement unit with a preset target value;
Controls the level of the burst signal output by the signal generator so that there is no difference between the measured output level and the target value when the determination unit determines that the measured output level is outside the target value. And a level control unit (50) for performing,
An RF communication device test apparatus, wherein the test is performed after the determination unit determines that the measured output level is within a target value.   2. The device test apparatus for RF communication according to claim 1, wherein the level measuring unit measures the output level by integrating over the section To. 3.   The level control unit controls the signal generation unit by sending a gain control signal reflecting a control amount for controlling the level of the burst signal to the signal generation unit every cycle Ta, and sends it to the previous cycle Ta. Based on the gain control signal and the comparison result of the determination unit at that time, a new control amount for controlling the signal generation unit so as to eliminate the level difference is estimated, and the new control amount is reflected. The RF communication device test apparatus according to claim 1 or 2, further comprising control amount estimation means (51) for sending the gain control signal to the signal generator.   The control amount estimation means holds in advance characteristic information indicating the control amount versus the output level representative of the RF communication device, and the determination result from the determination unit and the level setting means are the previous cycle. 4. The device test apparatus for RF communication according to claim 3, wherein the control amount is estimated with reference to the characteristic information based on the gain control signal at Ta.   The level control unit previously controls the past control amount reflected in the gain control signal by the control amount estimation unit when it is determined that the output level measured by the determination unit in the past test is within a target value. Initial control amount management means (52) for managing the control amount, and the control amount estimation means outputs the gain control signal reflecting the past control amount to the signal generator when starting the control. 5. The next control amount is estimated by using the gain control signal reflecting the past control amount as the gain control signal in the previous cycle Ta in the next cycle Ta. Device test apparatus for RF communication as described in 1. An operation unit (61) and a display unit (62);
The determination unit stores a representative test result distribution characteristic indicating a distribution of the result of the test with respect to a change in the target value. The test result distribution characteristic is stored in the test result distribution before the start of the test. Either the target value of the characteristic or the distribution of the result of the test is displayed on the display unit so that it can be specified on the operation unit, and when the target value is specified on the test result distribution characteristic, it is specified. Compare the target level corresponding to the specified test result from the representative distribution characteristic with the output level measured by the level measuring unit when the test result is specified. The RF communication device test apparatus according to claim 1, wherein the RF communication device test apparatus is set to perform the test. The target value includes an allowable level range and a specific level within the allowable level range,
The determination unit compares the output level measured by the level measurement unit with the specific level,
When the level control unit determines that the output level measured by the determination unit is outside a target value, the level difference between the output level measured by the level measurement unit and the specific level is eliminated. The level of the burst signal output by the signal generator is controlled, and when the determination unit determines that the output level measured by the level measurement unit is within the allowable level range, the burst signal at that time The device test apparatus for RF communication according to any one of 1 to 6, wherein the level is maintained. A modulation signal obtained by modulating a baseband signal with an RF signal is output to the outside, and a burst signal generated so as to include the modulation signal in the interval To within the period Ta is input to the RF communication device, An RF communication device test method for receiving an output of a communication device and testing the RF communication device,
A baseband signal having a period Ta, and the baseband signal having a level that changes with time in each period Ta is the same in any period Ta, and the baseband signal is generated as the RF signal. A signal generation step of outputting the modulated signal modulated with a signal to the outside;
A level measurement step of receiving an output from the external RF communication device and measuring an output level in the section To in synchronization with the period Ta;
A determination step of comparing the output level measured by the level measurement unit with a preset target value;
Controls the level of the burst signal output by the signal generator so that there is no difference between the measured output level and the target value when the determination unit determines that the measured output level is outside the target value. Level control stage to perform,
An RF communication device test method comprising: a test step of performing the test after the determination unit determines that the measured output level is within a target value.

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