JP5739499B2 - Burst signal measuring apparatus and measuring method - Google Patents

Description

  The present invention relates to a technique for measuring a burst signal used in digital communication, and more particularly to a technique for accurately performing time mask measurement defined by a communication standard for burst signals.

  The signal used for digital communication has an on-period and an off-period during which power is output. The signal level in the on-period is within the specified range, and the signal level in the off-period is below the specified value. The measurement target device is evaluated by measuring whether

  This measurement is generally called on / off time mask measurement. For example, in the communication standard 3GPP TS 36.521-1 V9.7.0, with respect to General ON / OFF time mask, as shown in FIG. 6, an on period Ton in which a signal subframe is output and an off period Toff1 before and after the on period Ton, Toff2 is defined, and the average level Lon during the ON period Ton falls within the allowable range of A ± a indicated by hatching, and the average levels Loff1 and Loff2 during the OFF periods Toff1 and Toff2 fall below the allowable value of B It prescribes. Note that non-measurement time zones Tnm1 and Tnm2 are provided between the on period and the off periods before and after the on period, taking into account the rise and fall times of the signal.

  In addition to the General ON / OFF time mask for measuring burst signals of subframes as described above, the PRACH ON / OFF time mask for measuring burst signals of PRACH (physical random access channel), SRS ON / OFF time mask is also specified.

  Therefore, in order to perform such measurement quantitatively, a burst signal output from a measurement target such as a portable terminal or a base station apparatus is received by a receiving unit, and this is converted into a digital value by an A / D converter. It is necessary to acquire level data in the on-period and off-periods before and after the on-period.

  However, the dynamic range of the burst signal to be measured is 60 dB or more in some cases, and the dynamic range on the measuring instrument side required for accurately measuring the maximum level and the minimum level is at least 80 dB or more. In general, it is difficult to satisfy the dynamic range of the entire data acquisition unit including the reception unit and the A / D converter.

  As a technology for solving this, data acquisition in a low gain mode that can accurately acquire a high signal level in an on period for a burst signal to be measured and a signal level that can be accurately acquired in a low off period can be acquired. By performing data acquisition in the high gain mode, a method for accurately obtaining the levels of the on period and the off period is realized.

  As described above, for example, Patent Literature 1 discloses a technique for accurately obtaining the level of the off period and the on period using data of burst signals acquired with different gains in order to compensate for the shortage of the dynamic range on the measuring instrument side. It is disclosed.

JP-A-6-289077

  However, some measurement target devices do not perform power output control at a correct timing with respect to an on period or an off period defined by a communication method.

  For example, as shown in FIG. 7, even if there is a device that performs control such that the timing when the burst signal becomes high level is earlier than specified and protrudes to the off period Toff1 side, the conventional device does not recognize this. The mask level is determined by obtaining the average level in the specified on period Ton from the data obtained in the low gain mode and obtaining the average level in the prescribed off periods Toff1 and Toff2 from the data obtained in the high and low gain mode. Become.

  Here, even if the level of the protruding portion to the off period Toff1 does not reach the saturation level even when it is acquired in the high gain mode, the level of the protruding portion is also accurate, so it is accurately reflected in the average level in the entire off period Toff1. There is no problem because it is done.

  However, if the level of the protruding part to the off period Toff1 reaches the saturation level when acquired in the high gain mode, the average level of that part becomes smaller than the average level of the actual protruding part, and this is included. The average level of the entire off period Toff1 is smaller than the average level of the input burst signal during the off period Toff1, and accurate measurement cannot be performed. This problem occurs in the same way even when the other off-period Toff2 protrudes, and there is a problem that the prescribed mask measurement cannot be performed accurately for the input burst signal.

  The present invention solves this problem, and the timing when the burst signal becomes high level with respect to the specified on period or off period is too early, or the timing when it becomes low level is delayed, and the burst signal protrudes into the off period Even so, an object of the present invention is to provide a burst signal measuring apparatus and a measuring method thereof capable of performing a correct time mask measurement.

In order to achieve the above object, a burst signal measuring apparatus according to claim 1 of the present invention comprises:
A burst signal to be measured is defined by the communication system, and an on period in which the signal level is expected to be high and an off period in which the signal level is expected to be low before and after the on period are received. A low gain mode in which a high level signal expected to be input during the on period is desaturated, and a low level signal expected to be input during the off period is desaturated A data acquisition unit (21) having a high gain mode acquired at
An on / off level calculation unit that obtains the average level of the on period and the average level of the off periods before and after the level data acquired by the data acquisition unit in the low gain mode and the level data acquired in the high gain mode. (30),
A burst signal having a determination unit (40) for determining whether or not an average level of the on period and the off period before and after the on period obtained by the on / off level calculation unit conforms to a mask defined by the communication method. In the measuring device,
The on / off level calculation unit includes:
On-level calculation means (31) for obtaining an average level of the on-period from the level data acquired by the data acquisition unit in the low gain mode and outputting the average level to the determination unit;
Level data exceeding a predetermined threshold set between a high signal level expected to be input during the ON period of the burst signal and a low signal level expected to be input during the OFF period. Determining whether or not the level data acquired in the low gain mode is in the off period, and if there is, the period in which the level data exceeds the threshold value in the off period is determined as an overhang period Detection means (32);
When the protrusion period is detected in the off period preceding the on period, an average level of the protrusion period in the level data acquired in the low gain mode is obtained as a preceding protrusion amount, and the protrusion period is the on period. A protrusion amount calculating means (33) for obtaining an average level of the protrusion period in the level data acquired in the low gain mode as a subsequent protrusion amount when detected in the off period at the latter stage of the period;
When the protrusion period is not detected, average levels of the off periods before and after the on period are respectively obtained from the level data acquired in the high gain mode, and the protrusion period is set to the off period before the on period. If detected, an average level of a period excluding the protruding period from the off period of the preceding stage is obtained from the level data acquired in the high gain mode, and the preceding stage is calculated from the average level and the preceding protruding amount. The average level of the entire off period is obtained, and when the protrusion period is detected in the subsequent off period, the protrusion period is calculated from the subsequent off period from the level data acquired in the high gain mode. The average level of the excluded period is calculated, and the average level of the entire subsequent off-period is determined from the average level and the amount of protrusion of the latter stage. Characterized by comprising a off-level calculating means (34) that.

Moreover, the burst signal measurement method of claim 2 of the present invention comprises:
A burst signal to be measured is defined by the communication system, and an on period in which the signal level is expected to be high and an off period in which the signal level is expected to be low before and after the on period are received. High gain where low level signal expected to be input during the off period is acquired in low gain mode where the high level signal expected to be input during the on period is desaturated and low level signal expected to be input during the off period Data acquisition stage to acquire in mode,
An on / off level calculation step for obtaining an average level of the on period and an average level of the off period before and after the level data from the level data acquired in the low gain mode and the level data acquired in the high gain mode;
In the burst signal measurement method, including a determination step of determining whether an average level of the on period and the off period before and after the on period conforms to a mask defined by the communication method,
The on / off level calculation step includes:
From the level data acquired in the low gain mode, an on level calculation step for obtaining an average level of the on period;
Level data exceeding a predetermined threshold set between a high signal level expected to be input during the ON period of the burst signal and a low signal level expected to be input during the OFF period. Determining whether or not the level data acquired in the low gain mode is in the off period, and if there is, the period in which the level data exceeds the threshold value in the off period is determined as an overhang period A detection stage;
When the protrusion period is detected in the off period preceding the on period, an average level of the protrusion period in the level data acquired in the low gain mode is obtained as a preceding protrusion amount, and the protrusion period is the on period. A protrusion amount calculating step for obtaining an average level of the protrusion period in the level data acquired in the low gain mode as a subsequent protrusion amount when detected in the off period at the latter stage of the period;
When the protrusion period is not detected, average levels of the off periods before and after the on period are respectively obtained from the level data acquired in the high gain mode, and the protrusion period is set to the off period before the on period. If detected, an average level of a period excluding the protruding period from the off period of the preceding stage is obtained from the level data acquired in the high gain mode, and the preceding stage is calculated from the average level and the preceding protruding amount. The average level of the entire off period is obtained, and when the protrusion period is detected in the subsequent off period, the protrusion period is calculated from the subsequent off period from the level data acquired in the high gain mode. The average level of the excluded period is calculated, and the average level of the entire subsequent off-period is determined from the average level and the amount of protrusion of the latter stage. Characterized in that it comprises a off-level calculation step that.

  As described above, in the present invention, the protrusion of a high level signal with respect to the off period before and after the on period is detected, and when detected, the amount of the protrusion is accurately calculated from the level data of the off period acquired in the low gain mode. The level of the entire off period is obtained from the amount of protrusion and the average level of the period excluding the protruding part from the level data of the off period acquired in the high gain mode. Therefore, correct mask measurement can be performed.

Overall configuration diagram of an embodiment of the present invention Signal waveform diagram for explaining the operation of the embodiment Signal waveform diagram for explaining the operation of the embodiment Signal waveform diagram for explaining the operation of the embodiment The figure which shows another structural example of a data acquisition part Diagram for explaining mask measurement for burst signal Signal waveform diagram when there is a protrusion to the off period

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the overall configuration of a burst signal measuring apparatus 20 to which the present invention is applied.

  The burst signal measuring apparatus 20 includes a data acquisition unit 21, an on / off level calculation unit 30, a determination unit 40, a waveform synthesis unit 50, and a display unit 60.

  As shown in FIG. 2A, the data acquisition unit 21 includes an on period Ton in which the signal level is expected to be high, and off periods Toff1 and Toff2 in which the signal level is expected to be low before and after the on period Ton. Receives the burst signal Sv to be measured defined by the communication method, but the level (power level) waveform of the input burst signal Sv has a very large level difference as shown in FIG. In the signal processing of one gain, it is difficult to measure accurately because the high level portion is saturated or the low level portion is buried in noise. Therefore, the data acquisition unit 21 acquires the level data in a low gain mode in which a high level signal expected to be input in the on period Ton is non-saturated at a high S / N, and the off period Toff1. , And a high gain mode in which a low level signal expected to be input to Toff2 is acquired in a state of high S / N and desaturation.

  In the form of acquiring the level data in the low gain mode and the level data in the high gain mode, two types of level data are acquired by inputting a burst signal to a single signal path and changing the gain with time. In addition, a mode in which burst signals are simultaneously applied to two signal paths having different gains to acquire two types of level data can be employed.

  The example of FIG. 1 is the former form, and the data acquisition unit 21 includes a gain variable unit 22, a frequency converter 23, an A / D converter 24, a data conversion unit 25, a data memory 26, and a control unit 27 that controls them. It is constituted by.

  The gain variable unit 22 includes a variable attenuator, a variable gain amplifier, and the like, and allows the input burst signal Sv to pass through at a low gain (for example, a gain of −30 dB) and a high gain (for example, a gain of 0 dB). The high gain mode can be switched.

  The frequency converter 23 is of a heterodyne type that converts a high-frequency burst signal Sv of, for example, several hundred MHz to several GHz into an intermediate frequency band burst signal Sv ′ that can be processed by the A / D converter 24. If the frequency of the burst signal to be measured is low, this frequency converter 23 can be omitted. In the following description, the gain of the frequency converter 23 is set to 0 dB so that the invention can be easily understood. However, when there is a gain other than 0 dB (including attenuation), the gain and the gain of the variable gain device 22 are What is necessary is just to correct | amend the input level of a burst signal by the sum.

  The A / D converter 24 samples the input burst signal Sv ′ at a predetermined sampling period (a period corresponding to a frequency that is at least twice the intermediate frequency band), converts the sampled signal into a digital signal string Dv, and performs data conversion. To the unit 25.

  The data converter 25 receives the digital signal sequence Dv output from the A / D converter 24, converts the instantaneous waveform of the burst signal into level data (detection data), and converts the converted level data into a data memory. 26. Here, it is assumed that the level data obtained by the data converting unit 25 corresponds to the level (power) of the input burst signal with the gain (for example, −30 dB, 0 dB) of the gain variable unit 22 corrected. .

  For example, if the level of the digital signal sequence Dv obtained in the low gain mode is A, the level data Ds (L) is obtained by correcting the level A by a gain of −30 dB, and the digital signal obtained in the high gain mode is obtained. If the level of the signal sequence Dv is B, the level data Ds (H) is obtained by correcting the level B by 0 dB for the gain. This correction may be performed by an on / off level calculation unit 30 described later.

  The data memory 26 is provided with at least two memory areas 26a and 26b. In one memory area 26a, for example, as shown in FIG. 2C, a series of burst signals acquired in the low gain mode. Level data Ds (L) is stored, and the other memory area 26b stores level data Ds (H) of the burst signal obtained in the high gain mode, as shown in FIG.

  Here, in the level data Ds (L) shown in FIG. 2C, since the gain is low, the high level portion during the ON period of the burst signal does not saturate and the gain variable 22 is used as described above. By correcting the amount obtained, an accurate level can be obtained, but the low level portion during the off period is below the noise floor, and an accurate level cannot be obtained. In addition, in the level data Ds (H) shown in FIG. 2D, since the gain is high, the high level portion during the ON period of the burst signal is saturated and an accurate level cannot be obtained. Since the middle low level is sufficiently higher than the noise floor, it is possible to obtain an accurate level by correcting the gain of the gain variable unit 22.

  The control unit 27 specifies the input timing of the burst signal to be measured in the entire frame including the burst signal, and switches the gain of the gain variable device 22 and synchronizes the level data in synchronization with the input timing. Timing control such as switching of a write area to the data memory 26 is performed. More specifically, the digital signal sequence Dv output from the A / D converter 24 is received, data demodulation processing corresponding to the digital modulation method is performed, and the position of known unique data included in the demodulated data Then, the reference timing of the burst signal is specified, and a process for determining a specified on period and off period from the reference timing is also performed. Correspondence between the start and end timing of each period and the address information of the data memory 26 Time information indicating the relationship is given to the on / off level calculation unit 30 and the waveform synthesis unit 50. Since these processes are equivalent to the processes described in Patent Document 1, they will not be described in detail here.

  When the series of level data Ds (L) and Ds (H) for each of the low gain mode and the high gain mode is acquired in the data memory 26 of the data acquisition unit 21 in this way, the on / off level calculation unit 30 calculates the on period. The average level Lon and the average levels Loff1 and Loff2 of the off periods before and after the average level Lon are obtained, and the average levels of the on period and the off period obtained by the determination unit 40 are determined in advance in a communication method in which a burst signal to be measured is used. It is determined whether the specified mask is met.

  Here, the on / off level calculation unit 30 has a function of preventing a measurement error due to protrusion of the high level signal to the off period.

  That is, the on / off level calculation unit 30 includes an on level calculation unit 31, a protrusion detection unit 32, a protrusion amount calculation unit 33, and an off level calculation unit 34.

  As shown in FIG. 2C, the on-level calculation means 31 calculates the average level Lon of the on-period Ton from the series of level data Ds (L) acquired by the data acquisition unit 21 in the low gain mode. Obtain and output to the determination unit 40.

  Further, the protrusion detection means 32 has a high signal level (for example, −1 ± 7.5 dBm) expected to be input during the ON period Ton of the burst signal and a low signal expected to be input during the OFF periods Toff1 and Toff2. A predetermined threshold value R (for example, −30 dBm) is set between the level (for example, −50 dBm) and the threshold of the series of level data Ds (L) acquired by the data acquisition unit 21 in the low gain mode is set. It is determined whether or not level data exceeding the value R exists in the off periods Toff1 and Toff2, and if there is, the period in which the level data exceeds the threshold value R is obtained as the protruding periods Tov1 and Tov2. Note that the example of FIG. 2 shows a case where the overhang period is not detected.

  FIG. 3 (a) shows a case where a protruding period Tov1 exceeding the threshold value R in the series of level data Ds (L) acquired by the data acquisition unit 21 in the low gain mode is detected in the off period Toff1. FIG. 4A shows a case where the overhang period Tov2 exceeding the threshold value R is detected in the off period Toff2.

  As shown in FIG. 3A, the protrusion amount calculation means 33 calculates the average of the protrusion period Tov1 detected in the preceding off period Toff1 from the series of level data Ds (L) acquired in the low gain mode. The level is obtained as the preceding protrusion amount Lov1, and as shown in FIG. 4A, the average level of the protrusion period Tov2 detected in the latter off period Toff2 is obtained as the latter protrusion amount Lov2. The average level in the protruding period is obtained from a series of level data Ds (L) acquired in the low gain mode. In the low gain mode, the data exceeding the threshold value R is not saturated, and the high S / N Can be obtained with high accuracy.

  When the protrusion period is not detected by the protrusion detection means 32, the off level calculation means 34, as shown in FIG. 2D, the level data Ds (H acquired by the data acquisition unit 21 in the high gain mode. ), Average levels Loff1 and Loff2 of the off periods Toff1 and Toff2 before and after the on period Ton are obtained and output to the determination unit 40, respectively.

  In addition, when the protruding period Tov1 is detected in the preceding off period Toff1, as shown in FIG. 3 (b), the preceding stage off is included in the level data Ds (H) acquired in the high gain mode. The average level Loff1 ′ of the period Toff1 ′ excluding the protruding period Tov1 from the period Toff1 is obtained, and the average level Loff1 of the entire preceding off period Toff1 is obtained from the average level Loff1 ′ and the preceding protruding amount Lov1.

  Similarly, when a protruding period Tov2 is detected in the latter off period Toff2, the latter stage of the level data Ds (H) acquired in the high gain mode as shown in FIG. 4B. The average level Loff2 'of the period Toff2' excluding the protruding period Tov2 from the off period Toff2 is obtained, and the average level Loff2 of the entire subsequent off period Toff2 is obtained from this average level Loff2 'and the subsequent protruding amount Lov2.

These processes can be realized by the following calculation, for example.
Loff1 = {(Toff1 ′ × Loff1 ′) + (Tov1 × Lov1)} / Toff1
Loff2 = {(Toff2 ′ × Loff2 ′) + (Tov2 × Lov2)} / Toff2

  As described above, since the accurate amount of protrusion in the protrusion periods Tov1 and Tov2 is obtained and the average level of the entire off period is obtained, a burst signal in which a signal component having a high level protrudes in the off period is input. Even so, the average level of the entire off period can be obtained with high accuracy.

  The average levels Loff1 and Loff2 of the on period and off period obtained by the on / off level calculation unit 30 as described above are output to the determination unit 40. In the determination unit 40, it is determined whether or not the average levels Loff1 and Loff2 of the on period and the off period conform to a time mask defined in advance for the burst signal to be measured.

  That is, the average level Lon during the on period is within a predetermined allowable range, for example, −1 ± 7.5 dBm, and the average levels Loff1 and Loff2 during the off period are within a predetermined allowable value, for example, −48.5 dBm or less. If it is entered, it is determined that it is suitable for the time mask.

  The waveform synthesis unit 50 synthesizes the level waveform of the input burst signal from the level data stored in the data memory 26. This processing includes, for example, a high signal level expected to be input in the on period Ton and a low signal level expected to be input in the off periods Toff1 and Toff2 among a series of level data acquired in the low gain mode. Among the level data of the period Th whose level is higher than a predetermined threshold R ′ (which may be equal to the threshold R) set during the period and the level data acquired in the high gain mode, the period Th By connecting the level data of the period excluding the upper and lower parts along the time axis, the power level waveform of the actually input burst signal as shown in FIG. 2B is obtained.

  The display unit 60 displays the average level of the on period and the off period obtained by the on / off level calculation unit 30, the determination result of the determination unit 40, the power level waveform of the burst signal obtained by the waveform synthesis unit 50, and the like.

  In the above embodiment, the data acquisition unit 21 acquires two types of level data of the low gain mode and the high gain mode by inputting a burst signal to a single signal path and changing its gain with time. However, as described above, it is also possible to obtain two types of level data by simultaneously giving burst signals to two signal paths having different gains.

  FIG. 5 is a configuration example of the data acquisition unit 21 that realizes this, and an input burst signal Sv is given to fixed gain devices 22A and 22B having different gains (for example, −30 dB and 0 dB), and their outputs are supplied to the frequency The frequency converters 23A and 23B similar to the converter 23 respectively convert to the intermediate frequency band, and the outputs Sv (L) ′ and Sv (H) ′ are converted into digital signal sequences Dv by the A / D converters 24A and 24B. (L) and Dv (H). Then, these two signal sequences Dv (L) and Dv (H) are converted into level data Ds (L) and Ds (H) by the data converter 25 as described above, and stored in the data memory 26. The processing for the stored level data is the same as described above.

  In the above embodiment, the power level waveform of the input burst signal is synthesized and displayed. However, the waveform synthesis unit 50 and the display unit 60 for displaying the waveform are not essential requirements of the present invention. The present invention can also be applied to a system that transmits an average level of a period and a determination result by the determination unit 40 to another device.

  DESCRIPTION OF SYMBOLS 20 ... Burst signal measuring device, 21 ... Data acquisition part, 22 ... Gain variable, 22A, 22B ... Fixed gain, 23, 23A, 23B ... Frequency converter, 24, 24A, 24B ... A / D converter, 25... Data conversion unit, 26... Data memory, 27... Control unit, 30 .. ON / OFF level calculation unit, 31... ON level calculation unit, 32. Quantity calculation means 34... Off level calculation means 40... Judgment part 50... Waveform synthesis part 60.

Claims (2)

A burst signal to be measured is defined by the communication system, and an on period in which the signal level is expected to be high and an off period in which the signal level is expected to be low before and after the on period are received. A low gain mode in which a high level signal expected to be input during the on period is desaturated, and a low level signal expected to be input during the off period is desaturated A data acquisition unit (21) having a high gain mode acquired at
An on / off level calculation unit that obtains the average level of the on period and the average level of the off periods before and after the level data acquired by the data acquisition unit in the low gain mode and the level data acquired in the high gain mode. (30),
A burst signal having a determination unit (40) for determining whether or not an average level of the on period and the off period before and after the on period obtained by the on / off level calculation unit conforms to a mask defined by the communication method. In the measuring device,
The on / off level calculation unit includes:
On-level calculation means (31) for obtaining an average level of the on-period from the level data acquired by the data acquisition unit in the low gain mode and outputting the average level to the determination unit;
Level data exceeding a predetermined threshold set between a high signal level expected to be input during the ON period of the burst signal and a low signal level expected to be input during the OFF period. Determining whether or not the level data acquired in the low gain mode is in the off period, and if there is, the period in which the level data exceeds the threshold value in the off period is determined as an overhang period Detection means (32);
When the protrusion period is detected in the off period preceding the on period, an average level of the protrusion period in the level data acquired in the low gain mode is obtained as a preceding protrusion amount, and the protrusion period is the on period. A protrusion amount calculating means (33) for obtaining an average level of the protrusion period in the level data acquired in the low gain mode as a subsequent protrusion amount when detected in the off period at the latter stage of the period;
When the protrusion period is not detected, average levels of the off periods before and after the on period are respectively obtained from the level data acquired in the high gain mode, and the protrusion period is set to the off period before the on period. If detected, an average level of a period excluding the protruding period from the off period of the preceding stage is obtained from the level data acquired in the high gain mode, and the preceding stage is calculated from the average level and the preceding protruding amount. The average level of the entire off period is obtained, and when the protrusion period is detected in the subsequent off period, the protrusion period is calculated from the subsequent off period from the level data acquired in the high gain mode. The average level of the excluded period is calculated, and the average level of the entire subsequent off-period is determined from the average level and the amount of protrusion of the latter stage. Burst signal measuring apparatus characterized by comprising a off-level calculating means (34) that. A burst signal to be measured is defined by the communication system, and an on period in which the signal level is expected to be high and an off period in which the signal level is expected to be low before and after the on period are received. High gain where low level signal expected to be input during the off period is acquired in low gain mode where the high level signal expected to be input during the on period is desaturated and low level signal expected to be input during the off period Data acquisition stage to acquire in mode,
An on / off level calculation step for obtaining an average level of the on period and an average level of the off period before and after the level data from the level data acquired in the low gain mode and the level data acquired in the high gain mode;
In the burst signal measurement method, including a determination step of determining whether an average level of the on period and the off period before and after the on period conforms to a mask defined by the communication method,
The on / off level calculation step includes:
From the level data acquired in the low gain mode, an on level calculation step for obtaining an average level of the on period;
Level data exceeding a predetermined threshold set between a high signal level expected to be input during the ON period of the burst signal and a low signal level expected to be input during the OFF period. Determining whether or not the level data acquired in the low gain mode is in the off period, and if there is, the period in which the level data exceeds the threshold value in the off period is determined as an overhang period A detection stage;
When the protrusion period is detected in the off period preceding the on period, an average level of the protrusion period in the level data acquired in the low gain mode is obtained as a preceding protrusion amount, and the protrusion period is the on period. A protrusion amount calculating step for obtaining an average level of the protrusion period in the level data acquired in the low gain mode as a subsequent protrusion amount when detected in the off period at the latter stage of the period;
When the protrusion period is not detected, average levels of the off periods before and after the on period are respectively obtained from the level data acquired in the high gain mode, and the protrusion period is set to the off period before the on period. If detected, an average level of a period excluding the protruding period from the off period of the preceding stage is obtained from the level data acquired in the high gain mode, and the preceding stage is calculated from the average level and the preceding protruding amount. The average level of the entire off period is obtained, and when the protrusion period is detected in the subsequent off period, the protrusion period is calculated from the subsequent off period from the level data acquired in the high gain mode. The average level of the excluded period is calculated, and the average level of the entire subsequent off-period is determined from the average level and the amount of protrusion of the latter stage. Burst signal measurement method characterized by including the off-level calculation step that.

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