JP4091624B2 - Modulation signal analyzer - Google Patents

Description

  The present invention relates to a modulation signal analysis apparatus that analyzes an input modulation signal, and more particularly, to a modulation signal analysis apparatus that analyzes a constellation that is a characteristic capable of visually evaluating the modulation quality of the modulation signal.

  In the mobile communication system, as shown in FIG. 13, signals are exchanged between the base station 1 and each mobile phone 2a, 2b, 2c, 2d as each mobile terminal. A signal transmitted from the base station 1 to each of the mobile phones 2a to 2d is, for example, a modulated signal a that is phase-modulated and spectrum-spread (CDMA).

FIG. 14 is a schematic configuration diagram of the base station 1. Transmission data D ₁ , D ₂ ,..., D _n of each channel CH ₁ , CH ₂ ,..., CH _n transmitted to each mobile phone 2 a, 2 b, 2 c, 2 d are respectively transmitted locally by the modulation unit 3. The signal LO is phase-modulated by a modulation scheme such as QPSK, and is spread by the code spreading unit 4 with each of the spreading codes C ₁ , C ₂ ,..., C _n. After being amplified with gains G ₁ , G ₂ ,..., G _n corresponding to the distances LD _{1 to} LD _n from the base station 1 to the corresponding mobile phones 2 a to 2 d, they are input to the adder 6.

The adder 6 adds the modulated signals b ₁ , b ₂ ,..., B _n after amplification of the channels CH ₁ , CH ₂ ,..., CH _n and sends the modulated signals after the addition to the frequency converter 7. . The frequency conversion unit 7 raises the frequency of the modulated signal after addition to the GHz band and emits the radio wave from the antenna 8 as the modulation signal a described above.

  Each of the mobile phones 2a to 2d receives the modulated signal a emitted from the antenna 8 of the base station 1, despreads the modulated signal a with the spreading code C given to the mobile phone 2a to 2d, Is extracted, and the self-modulated signal is demodulated to obtain transmission data D addressed thereto.

  When the modulation signal analyzer analyzes that the data is correctly phase-modulated in the signal quality of the modulation signal a output from the base station 1, the modulation state can be visually evaluated. It is common practice to measure the constellation and display it on a display (see Patent Document 1).

As shown in FIG. 4A, this constellation is obtained by orthogonally demodulating the modulation signal a to be analyzed into I and Q symbol data in symbol units, and converting the I and Q symbol data at each symbol position to IQ. This is represented as a measurement point 30 on the coordinates. The experimenter evaluated the modulation quality from the positional relationship between the ideal point 33 and the measurement point 30 displayed on the IQ coordinates.
JP 2004-328503 A

However, when the modulation signal a is a sum of a plurality of modulation signals b ₁ , b ₂ ,..., B _n as shown in FIG. 14, as shown in FIGS. Many ideal points appear on the coordinates.

FIGS. 15A and 15B are displayed on the IQ coordinates in the two modulation signals b ₁ and b ₂ in a state where the gain G ₁ = G ₂ equal to the power adjustment unit 5 is applied. Indicates the ideal point. Since the modulation method is QPSK, there are four ideal points [(A ₁ , A ₂ , A ₃ , A ₄ ), (B ₁ , B ₂ , B ₃ , B ₄ ), respectively. FIG. 15C shows an ideal point displayed on the IQ coordinate in the modulation signal obtained by adding _two modulation signals b ₁ and b ₂ . As shown in the figure, there are nine ideal points.

FIGS. 16A and 16B show IQs in two modulated signals b ₁ and b ₂ in a state where different gains (G ₂ = 1.5G _{1 )} are applied to the power adjustment unit 5. Indicates the ideal point displayed on the coordinates. Since the modulation method is QPSK, there are four ideal points as in the above example. FIG. 16C shows an ideal point displayed on the IQ coordinate in a modulation signal obtained by adding _two modulation signals b ₁ and b ₂ . As shown in the figure, there are 16 ideal points.

Thus, the number and position of the ideal points displayed on the IQ coordinates in the modulation signal a obtained by adding a plurality of modulation signals b ₁ , b ₂ ,..., B _n are the modulation signals b ₁ , b _2. , ..., addition number of b _n, the gain G _1, G ₂ to be applied, ..., varies according to the value of G _n. Since the values of the gains G ₁ , G ₂ ,..., G _n change according to the distances LD _{1 to} LD _n from the base station 1 to the corresponding mobile phones 2a to 2d as described above, the number of ideal points , And the position is constantly changing.

  Accordingly, when such a constellation of the modulation signal a is calculated and the I and Q symbol data at each symbol position are represented as measurement points on the IQ coordinates, a large number of measurement points are represented by IQ. Since it is distributed over a wide range on the coordinates, it is not possible to easily determine on the display screen which ideal point each measurement point corresponds to, and the modulation quality can be easily determined from the positional relationship between the displayed ideal point and the measurement point. There is a problem that cannot be evaluated.

  The present invention has been made in view of such circumstances. Even if the modulation signal has many constellation ideal points and the position of the constellation is not constant, it can be obtained by calculating the constellation for the modulation signal to be analyzed. Modulation that can grasp at a glance the positional relationship of each measurement point with respect to the corresponding ideal point on the obtained IQ coordinates, easily understand the modulation quality of the modulation signal to be analyzed, and greatly improve operability and usability An object is to provide a signal analyzing apparatus.

  In order to solve the above-described problems, the present invention provides a modulation signal analysis apparatus that analyzes an input modulation signal and displays the analysis result on a display unit. The input modulation signal is converted into I and Q symbol data in symbol units. An input processing unit that performs orthogonal demodulation, a constellation calculation unit that calculates a constellation in which I and Q symbol data at each symbol position sequentially output from the input processing unit are represented as measurement points on IQ coordinates, A modulation method determination unit that determines the modulation method of the modulation signal from the constellation at each symbol position calculated by the modulation calculation unit, the modulation method determined by the modulation method determination unit, and the signal level of the I and Q symbol data Ideal point calculation unit for calculating each ideal point of the measurement, and each ideal point corresponding to each measurement point on IQ coordinates An EVM (error vector magnitude: error vector magnitude) calculation unit that calculates a vector connecting the two, and a vector at each measurement point calculated by the EVM calculation unit, the ideal point side end of the corresponding vector is IQ A vector translation calculation unit that translates so as to be located at the origin on the coordinates, and a display control unit that displays and outputs each vector on the IQ coordinates translated by the vector translation calculation unit on the display; It has.

  In the modulation signal analyzing apparatus configured as described above, the constellation of the input modulation signal is calculated, the modulation system is determined from this constellation, and the constellation of the constellation is determined from the modulation system and the signal level of the I and Q symbol data. Each ideal point is calculated, and a vector connecting each measurement point and each corresponding ideal point is calculated. Then, the vector at each measurement point is translated so that the ideal point side end of the vector is located at the origin on the IQ coordinates.

  Therefore, as a result, all ideal points of the constellation have been moved to the origin on the IQ coordinates, and by observing each vector translated to the origin, the correspondence of each measurement point of the constellation It is possible to immediately grasp the positional relationship with the ideal point.

  Therefore, even if the modulation signal has many ideal points for the constellation and its position is not constant, the experimenter can easily grasp the modulation quality of the modulation signal to be analyzed.

  In another aspect of the invention, the display control unit in the modulation signal analyzing apparatus according to the above-described aspect of the invention has circular coordinates with the origin as the center and the radial direction as the modulation error rate on the IQ coordinates displayed on the display. Overlapping display.

  In the modulation signal analyzing apparatus configured as described above, since circular coordinates are displayed with the origin at the center and the radial direction as the modulation error rate, a vector indicating the magnitude of the error from the ideal point at each measurement point is displayed. You can grasp the size at a glance.

  Further, a modulation signal analyzing apparatus according to another invention includes an input processing unit that orthogonally demodulates an input modulation signal to I and Q symbol data in symbol units, and I at each symbol position sequentially output from the input processing unit, A constellation calculation unit that calculates a constellation that expresses Q symbol data as measurement points on IQ coordinates, and a modulation that determines a modulation method of a modulation signal from the constellation at each symbol position calculated by the constellation calculation unit A method determination unit, an ideal point calculation unit that calculates each ideal point of the constellation from the modulation method determined by the modulation method determination unit and the signal level of the I and Q symbol data, and each measurement point on the IQ coordinates An EVM calculation unit that calculates a vector connecting each corresponding ideal point, and each measurement point calculated by the EVM calculation unit A phase error calculation unit for calculating a phase error for each corresponding ideal point, and the calculated vector of each measurement point, the ideal point side end of the corresponding vector is positioned at the origin on the IQ coordinates, and A vector rotational movement calculation unit that sets the direction of the end in a direction that is separated by a phase error calculated with respect to a reference direction defined on IQ coordinates, and the I rotationally moved by the vector rotational movement calculation unit A display control unit that displays and outputs each vector on the Q coordinate on a display;

  In the modulation signal analyzing apparatus configured as described above, the vector of each measurement point calculated by the EVM calculation unit is such that the ideal point side end of the corresponding vector is located at the origin on the IQ coordinates, and further, the corresponding vector Is set to a direction separated by a phase error calculated with respect to a reference direction defined on IQ coordinates. Therefore, the experimenter takes a glance at the display screen of the display, and shows the magnitude of the phase error from the ideal point of each measurement point (magnitude; magnitude of error) and the error direction of each measurement point. You can grasp at a glance.

  In another aspect of the invention, the display control unit in the modulation signal analyzing apparatus according to the above-described aspect of the invention calculates the vector of each measurement point on the IQ coordinate that has been translated or rotated, and the generation time between the measurement points. Display output on the display so that it can be identified.

  In the modulation signal analyzing apparatus configured as described above, the vector of each measurement point at each symbol position is translated or rotated to the origin on the IQ coordinates, and the generation time sequence of each measurement point is identified. By making such a display possible, it is possible to obtain one judgment material for investigating the cause of the modulation error.

  Another invention is the modulation signal analyzing apparatus according to the above-described invention, wherein the distance between the origins that calculates the distance between the origins that is the distance to the origin on the IQ coordinates at each ideal point calculated by the ideal point calculation unit. A calculation unit is provided, and the display control unit can identify the vector of each measurement point on the IQ coordinate that has been translated or rotated according to the distance between the origins of the ideal points corresponding to each measurement point. Display on the display.

  In the modulation signal analyzing apparatus configured as described above, the vector of each measurement point at each symbol position calculated by the constellation calculation unit is translated or rotated to the origin on the IQ coordinates, and The constellation is displayed and output as a constellation so that it can be identified according to the distance between the origins indicating the distance to the origin of the ideal point corresponding to the measurement point.

  In this way, by displaying the vector of each measurement point translated or rotated to the origin according to the distance between the origins of the ideal points in an identifiable manner, the cause of the modulation error can be investigated in the same manner as in the above-described invention. One decision material can be obtained.

  In the present invention, the display position of a vector indicating the magnitude of the modulation error connecting each measurement point and the ideal point on the IQ coordinate obtained by constellation calculation is moved to the origin on the IQ coordinate. Yes.

  Therefore, even if the modulation signal has many constellation ideal points and the position thereof is not constant, the corresponding measurement points on the IQ coordinates obtained by the constellation calculation for the modulation signal to be analyzed correspond to each other. The positional relationship with the ideal point can be grasped at a glance, the modulation quality of the modulation signal to be analyzed can be easily grasped, and the operability and usability can be greatly improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 and 2 are block diagrams showing a schematic configuration of a modulation signal analyzing apparatus according to an embodiment of the present invention. The same parts as those in FIGS. 13 and 14 are denoted by the same reference numerals, and detailed description of the overlapping parts is omitted.

In the modulation signal analyzing apparatus of this embodiment, a plurality of modulation signals b transmitted from the base station 1 described with reference to FIGS. 13 and 14 to the respective mobile phones 2a, 2b, 2c, and 2d as analysis target modulation signals. _This is a modulation signal a obtained by adding ₁ , b ₂ ,..., B _n .

  The high-frequency modulation signal a input from the input terminal 9 is frequency-converted to an intermediate frequency based on the frequency signal from the local oscillator (LOOSC) 12 by the frequency conversion unit 11 of the input processing unit 10 and then A / D converted. The digital signal is converted into a digital modulation signal a by the device 13 and input to the quadrature demodulation unit 14. The quadrature demodulator 14 demodulates the input digital modulation signal a into I (in-phase component) symbol data and Q (quadrature component) symbol data in symbol units, and sends them to the despreading unit 15.

The despreading unit 15 uses the spreading codes C ₁ , C ₂ ,..., C _n used in the code spreading unit 4 in FIG. 14 to convert the I and Q symbol data into the channels CH ₁ and CH described in FIG. ₂ ,..., Return to the I and Q symbol data for each CH _n and write to the symbol data memory 16. Therefore, in the symbol data memory 16, I and Q symbol data at each symbol position in the modulation signal a (each time position in the modulation signal a) is written in time series.

  The symbol data reading unit 17 sequentially reads the I and Q symbol data written in the symbol data memory 16 of the input processing unit 10 and sends them to the constellation calculation unit 18, the signal level measurement unit 19, and the frequency error calculation unit 20. To do.

  The frequency error calculation unit 20 measures the frequency (carrier frequency) of the modulation signal a from the period of the I and Q symbol data at each symbol position sequentially input from the symbol data reading unit 17, and a prescribed frequency determined by the standard Is calculated and written into the measurement data memory 23 together with the measured frequency.

  The constellation calculation unit 18 measures I and Q symbol data at each symbol position sequentially input from the symbol data reading unit 17 on a IQ point as a measurement point 30 on IQ coordinates as shown in FIG. The constellation 31 expressed as is calculated and written into the measurement data memory 23.

  Further, the constellation calculation unit 18 sends the constellation 31 at each calculated symbol position to the modulation scheme determination unit 21. The modulation method determination unit 21 determines the modulation method of the modulation signal a from the arrangement relationship of the measurement points 30 of the constellation 31 at each symbol position. More specifically, the selection is made from several predetermined modulation schemes (QPSK, 16QAM, etc.) that can be adopted for the modulation signal a. The modulation method determination unit 21 writes the determined modulation method into the measurement data memory 23 and sends it to the ideal point calculation unit 22.

The signal level measuring unit 19 calculates the signal level of the I and Q symbol data for each channel CH ₁ , CH ₂ ,..., CH _{n at} each symbol position sequentially input from the symbol data reading unit 17. Specifically, the signal level is obtained by [(I symbol data) ² + (Q symbol data) ² ] ^1/2 . That is, each modulation signal b _1, b ₂ constituting the modulated signal a, ..., b each gain of _{n G 1, G 2, ...} , is obtained the signal level corresponding to the value of G _n. The calculated signal levels are written to the measurement data memory 23 and sent to the ideal point calculation unit 22.

Ideal point calculation unit 22, the modulation scheme determining section 21 each modulation signal b ₁ constituting the determined modulation scheme and the modulation signal a in, b _2, ..., b _n of I, from the signal level of the Q symbol data, FIG. Each ideal point 33 of the constellation 31 shown in 4 (a) is calculated. The ideal point calculation unit 22 writes each calculated ideal point 33 to the measurement data memory 23 and adds the determined modulation method, and then includes an EVM calculation unit 24, a phase error calculation unit 25, an origin offset calculation unit 26, a vector This is sent to the rotational movement calculation unit 28 and the origin distance calculation unit 29.

  As shown in FIG. 4B, the EVM (error vector magnitude) calculating unit 24 connects the measurement point 30 in the calculated constellation 31 and the ideal point 33 at each symbol position in the modulation signal a. A vector (EVM) 35 is obtained. Further, as shown in FIG. 4C, an average EVM (RMS EVM) of vectors (EVM) at all symbol positions is obtained. The EVM (error vector magnitude) calculation unit 24 writes the calculated vector (EVM) 35 at each symbol position to the measurement data memory 23 and sends it to the vector parallel movement calculation unit 27 and the vector rotation movement calculation unit 28. Further, the EVM (error vector magnitude) calculation unit 24 writes the calculated average EVM (RMS EVM) into the measurement data memory 23.

  As shown in FIG. 4B, the phase error calculation unit 25 is between the measurement point 30 and the ideal point 33 in the calculated constellation 31 on the IQ coordinates at each symbol position in the modulation signal a. The phase error φ is calculated. When the measurement point 30 is located in the counterclockwise direction with respect to the ideal point 33, the phase error φ is a (+) sign, and when the measurement point 30 is located in the clockwise direction, the phase error φ is a (−) sign. The phase error calculation unit 25 writes the calculated phase error φ of each measurement point 30 into the measurement data memory 23 and sends it to the vector rotation movement calculation unit 28.

  As shown in FIG. 4 (d), the origin offset calculation unit 26 has each measurement point 30 in the calculated constellation 31 on the IQ coordinates, each ideal point 33, and each symbol position in the modulation signal a. The origin offset indicating the distance between the origin O ′ of the IQ coordinates of the measured constellation 31 and the origin O of the IQ coordinates of the logical (ideal) constellation is calculated from To write into the measurement data memory 23.

  As shown in FIGS. 5A to 5C, the vector translation calculator 27 measures each measurement point 30 (M, M, M) of the constellation 31 calculated by the EVM calculator 24 at each symbol position in the modulation signal a. The vector 35 connecting the coordinates (Im, Qm)) and the corresponding ideal point 33 (R1, coordinates (I1, Q1)) is located at the ideal point side end of the vector 35 at the origin O on the IQ coordinates. The vector 36 after the parallel movement is calculated and written into the measurement data memory 23. Specifically, the coordinates (0, 0) of the origin O side end of the vector 36 after translation and the coordinates (Im-I1, Qm-Q1) of the opposite side are obtained.

As shown in FIGS. 7A and 7B, the vector rotational movement calculation unit 28 measures each measurement point 30 (M ₁ ) of the constellation 31 calculated by the EVM calculation unit 24 at each symbol position in the modulation signal a. , M ₂ ) and the corresponding ideal point 33 (R ₁ , R ₂ ) corresponding to the vector 35, the ideal point 33 (R ₁ , R ₂ ) side end of the vector 35 is the origin on the IQ coordinates. While being located at O, the direction of the other end of the vector 35 is separated by the calculated phase error (φ _R1M1 , φ _R2M2 ) with respect to the I axis as the reference direction defined on the _{IQ coordinates} . The vector 37 after the rotational movement is calculated and written into the measurement data memory 23. Specifically, the coordinates (0, 0) of the origin O side end and the coordinates of the opposite end of the vector 37 after the rotational movement are obtained.

As shown in FIG. 11, the origin-to-origin distance calculation unit 29 has, for example, 16 ideal points 33 (R ₁ , R ₂ , R ₃ , R ₄ ,..., R ₁₅ ) of the constellation 31 on the IQ coordinates. , R ₁₆ ) and ₁₆ origin-to-origin distances 34 (L ₁ , L ₂ , L ₃ , L ₄ ,..., L ₁₅ , L ₁₆ ) indicating the distance between the origin O of the IQ coordinates. To write into the measurement data memory 23.

  In the measurement data memory 23, as shown in FIG. 3, the constellation 31 and the EVM calculation calculated by the constellation calculation unit 18 for each symbol No (number) 1 to n indicating each symbol position in the modulation signal a. The vector (EVM) 35 calculated by the unit 24, the vector 36 after the translation calculated by the vector translation calculation unit 27, the vector 37 after the rotation calculated by the vector rotational movement calculation unit 28, and the phase error calculation unit 25, the signal level measured by the signal level measuring unit 19, the frequency (error) calculated by the frequency error calculating unit 20, and the origin offset calculated by the origin offset calculating unit 26 are written. .

  When writing of measured values for all symbols No (numbers) 1 to n in the modulation signal a is completed, an average value of measured values over all symbols No (numbers) 1 to n is calculated, and the average value is input. Written.

Further, in the measurement data memory 23, the modulation method 32 of the modulation signal a determined by the modulation method determination unit 21 and the ideal point 33 (R ₁ , R ₂ ) in the constellation 31 calculated by the ideal point calculation unit 22 are stored. ,..., R _n ), and the distance 34 between the origins of the ideal points 33 (R ₁ , R ₂ ,..., R _n ) calculated by the distance calculation unit 29.

  In FIG. 2, each measurement data (calculation result) described above at each symbol position in the modulation signal a written in the measurement data memory 23 is read to the editing unit 38, and the operator (experimental) operation unit 40. Various editing processes including the color component editing process 39 and the circular coordinates 45 are performed based on the editing instruction via the. The display control unit 41 displays and outputs each edited measurement data on the display 42.

  As shown in FIG. 5D, the circular coordinates 45 are centered on the origin O displayed on the IQ coordinates displayed on the display 42, and the radial direction is, for example, the vectors 35, 36. , 37 are circular coordinates having a modulation error (%) indicated by EVM indicating the size (length) of 37.

  Hereinafter, a display example of the editing instruction and editing result on the display 42 via the operation unit 40 of the operator (experimental) will be described with reference to the drawings.

  In FIG. 6, the constellation 31 of two symbol positions (symbol Nos. 15 and 16) read from the measurement data memory 23, the edit constellation 43, and the measurement list 44 are displayed on the display unit 42. ing.

The constellation 31 includes four ideal points 33 (R ₁ , R ₂ , R ₃ , R ₄ ) and four measurement points 30 (A, B, C, D) are displayed. In the editing constellation 43, circular coordinates 45 are displayed in an overlapping manner on the IQ coordinates. In the circular coordinates 45, the vectors 36 obtained by translating the vectors 35 of the measurement points 30 (A, B, C, D) to the origin O position are displayed on the constellation 31.

  The measurement list 44 displays the modulation method, signal level, modulation error (%), phase error, origin offset, frequency error, and display symbol No. at any one of the symbol positions.

  In such an edit constellation 43, the vector 35 at each measurement point 30 of the constellation 31 is translated so that the end of the corresponding vector 30 on the ideal point 33 side is located at the origin O on the IQ coordinates. A new vector 36 is obtained.

Therefore, as a result, all ideal points 33 (R ₁ , R ₂ , R ₃ , R ₄ ) of the constellation 31 have been moved to the origin O on the IQ coordinates, and the tester can By observing each vector 36 translated to O, the corresponding ideal point 33 (R ₁ , R ₂ , R ₃ , R ₄ ) of each measurement point 30 (A, B, C, D) of the constellation 31 is observed. ) Immediately. Therefore, even if the modulation signal a has many ideal points 33 of the constellation 30 and the position thereof is not constant, the experimenter can easily grasp the modulation quality of the modulation signal a to be analyzed.

  Further, since the circular coordinates 45 having the origin 0 as the center and the radial direction as the modulation error are displayed on the IQ coordinates, a vector 35 indicating the magnitude of the error from the ideal point 33 of each measurement point 30; You can grasp the size of 36 at a glance.

  In addition, each vector 36 translated to the origin O on the IQ coordinates of the editing constellation 43 displayed on the display 42 in FIG. 6 is identified and displayed so that the time of occurrence can be identified between the measurement points 30. It is also possible to do. Specifically, each vector 36 is displayed in different colors in the order of occurrence time. In this case, the editing constellation 43 is composed of vectors 36 color-coded using the measurement points 30 at a number of symbol positions stored in the measurement data memory 23.

  In this way, by displaying each vector 36 translated in parallel to the origin in a color-coded manner in the order of generation time, it is possible to obtain one judgment material for investigating the cause of the modulation error from the form of temporal change of each vector 36.

  Further, each vector 36 translated from the origin O on the IQ coordinates of the editing constellation 43 displayed on the display 42 in FIG. 6 is converted into the distance 34 between the origins of the ideal points 33 corresponding to the respective measurement points 30. It is also possible to identify and display such that it can be identified. Specifically, the vectors 36 are displayed in different colors in order of the distance 34 between the origins. In this case, the editing constellation 43 is composed of the vectors 36 displayed in different colors using the measurement points 30 at a number of symbol positions stored in the measurement data memory 23.

  As described above, the vectors 36 translated in parallel to the origin are color-coded and displayed in the order of the distance 34 between the origins. For example, the cause of the large modulation error indicated by the size (length) of each vector 36 is the corresponding vector 36. It is possible to obtain one judgment material that the ideal point 33 is far from the origin O on the IQ coordinates.

  In FIG. 8, the constellation 31 of two symbol positions (symbol Nos. 15 and 16), the editing constellation 43a, and the measurement list 44 read from the measurement data memory 23 are displayed on the display unit 42. ing.

The constellation 31 includes four ideal points 33 (R ₁ , R ₂ , R ₃ , R ₄ ) and four measurement points 30 (A, B, C, D) are displayed. In the edit constellation 43a, vectors 37 obtained by rotating the vectors 35 of the measurement points 30 to the origin O position are displayed on the constellation 31 on the IQ coordinates.

  The measurement list 44 displays the modulation method, signal level, modulation error (%), phase error, origin offset, frequency error, and display symbol No. at any one of the symbol positions.

  In such an editing constellation 43a, the vector 35 at each measurement point 30 of the constellation 31 is positioned at the origin O on the IQ coordinates with the end of the corresponding vector 36 on the ideal point 33 side, and after rotation. The direction of the other end of the vector 37 is set in a direction separated by a phase error φ with respect to the I-axis direction.

Therefore, the experimenter takes a glance at the display screen of the display 42 and increases the magnitude from the ideal point 33 (R ₁ , R ₂ , R ₃ , R ₄ ) of each measurement point 30 (A, B, C, D). Thus, the magnitude of the error, the magnitude of the phase error from the ideal point 33 of each measurement point 30, and the phase error direction can be grasped at a glance.

  In addition, each vector 37 that has been rotationally moved to the origin O on the IQ coordinates of the editing constellation 43a displayed on the display 42 in FIG. 8 is identified and displayed so that the time of occurrence can be identified between the measurement points 30. It is also possible to do. Specifically, each vector 37 is displayed in different colors in the order of occurrence time. In this case, the editing constellation 43a is composed of the vectors 37 displayed in different colors by using the measurement points 30 at a number of symbol positions stored in the measurement data memory 23.

  Thus, by displaying each vector 37 rotated and moved to the origin in a color-coded manner in the order of generation time, one judgment material for investigating the cause of the modulation error can be obtained from the temporal change form of each vector 37.

  Further, each vector 37 rotated and moved to the origin O on the IQ coordinates of the editing constellation 43a displayed on the display 42 in FIG. 8 is converted into the distance 34 between the origins of the ideal points 33 corresponding to the respective measurement points 30. It is also possible to identify and display such that it can be identified. Specifically, the vectors 37 are displayed in different colors in order of the distance 34 between the origins. In this case, the editing constellation 43a is composed of the vectors 37 displayed in different colors using the measurement points 30 at a number of symbol positions stored in the measurement data memory 23.

  In this way, by displaying each vector 37 rotated and moved to the origin in a color-coded manner in the order of the distance 34 between the origins, for example, the cause of the large modulation error indicated by the size (length) of each vector 37 is that of the corresponding vector. One judgment material can be obtained that the ideal point 33 is far from the origin O on the IQ coordinates.

  In FIG. 10, an edit constellation 43b and a measurement list 44 read out from the measurement data memory 23 and displayed at a number of symbol positions (symbol Nos. 15, 16, 17, and 18) are displayed on the display unit 42. Yes.

  In the edit constellation 43b, four ideal points 33 on the IQ coordinates and a plurality of measurement points 30 corresponding to the ideal point 33 for each ideal point 33 are generated in the order of occurrence time (symbol No). Can be identified, the color edit processing unit 9 of the editing unit 38 is activated and displayed in different colors.

  The technical meaning of displaying the plurality of measurement points 30 by the color indicating the generation time sequence will be described with reference to FIGS. For example, as shown in FIG. 9A, when the measurement points 30 are arranged in the circumferential direction indicated by the arrows in the order of occurrence time (1, 2, 3, 4, 5), the modulation signal a This indicates that there is a high possibility that the carrier frequency is shifted by a certain amount with respect to the specified frequency.

  Further, as shown in FIG. 9B, the measurement points 30 are not arranged in the order of time of occurrence in the circumferential direction (2, 5, 1, 3, 4). It can be determined that noise is mixed.

  In this manner, by displaying each measurement point 30 at each symbol position so that the generation time order can be identified, one judgment material for investigating the cause of the modulation error can be obtained.

  In FIG. 12, an edit constellation 43 c of all symbol positions (symbol Nos. 1 to n) of the modulation signal a read from the measurement data memory 23 and a measurement list 44 are displayed on the display 42. ing.

In the edit constellation 43c, 16 types of measurement points 30 (M ₁ , M ₂ , M ₃ , M ₄ ,..., M ₁₅ , M ₁₆ ) correspond to the self on the IQ coordinates. The distance between the origins 34 (L ₁ , L ₂ , L ₃ , L ₄ ,...) Of ₁₆ ideal points 33 (R ₁ , R ₂ , R ₃ , R ₄ ,..., R ₁₅ , R ₁₆ ) shown in FIG. L _15, L ₁₆₎ is displayed color separation for each.

  In general, as shown in FIGS. 11 and 16, when there are many ideal points 33 on the IQ coordinates, the magnitude of the error at the measurement point 30 corresponding to the ideal point 33 far from the origin 0 is Compared to the magnitude of the error at the measurement point 30 corresponding to the ideal point 33 close to the origin O, it tends to increase. Therefore, as shown in FIG. 12, by displaying each measurement point 30 in an identifiable manner in accordance with the distance 34 between the origins of the ideal point 33, it is possible to obtain one judgment material for investigating the cause of the modulation error.

The block diagram which shows schematic structure of the modulation signal analysis apparatus concerning one Embodiment of this invention of this invention The block diagram which shows the structure of a part of modulation signal analysis apparatus concerning the embodiment The figure which shows the memory content of the measurement data memory provided in the modulation signal analyzer concerning the embodiment The figure for demonstrating the modulation analysis operation | movement principle of the modulation signal analysis apparatus concerning the embodiment The figure which shows the vector translation of the modulation signal analyzer concerning the embodiment The figure which shows the analysis result of the modulation signal displayed on the indicator of the modulation signal analysis apparatus concerning the embodiment The figure which shows the vector rotational movement of the modulation signal analyzer concerning the embodiment The figure which shows the analysis result of the modulation signal displayed on the indicator of the modulation signal analysis apparatus concerning the embodiment The figure for demonstrating the characteristic of the identification display of the generation time order of the measurement point of the modulation signal analyzer concerning the embodiment The figure which shows the analysis result of the modulation signal displayed on the indicator of the modulation signal analysis apparatus concerning the embodiment The figure which shows the calculation method of the distance between origins of the modulation signal analyzer concerning the embodiment The figure which shows the analysis result of the modulation signal displayed on the indicator of the modulation signal analysis apparatus concerning the embodiment Diagram showing the relationship between base stations and mobile phones Schematic configuration diagram of base station Diagram for explaining the number of ideal points included in the constellation in the modulation signal The figure for demonstrating the number of the ideal points contained in the constellation in a modulation signal similarly

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Base station, 2a-2d ... Mobile phone, 3 ... Modulation part, 4 ... Code spreading | diffusion part, 5 ... Power adjustment part, 6 ... Adder, 10 ... Input processing part, 11 ... Frequency conversion part, 13 ... A / D converter, 14 ... orthogonal demodulator, 15 ... inverse transformer, 16 ... symbol data memory, 17 ... symbol data read unit, 18 ... constellation calculator, 19 ... signal level measuring unit, 20 ... frequency error calculator, DESCRIPTION OF SYMBOLS 21 ... Modulation system determination part, 22 ... Ideal point calculation part, 23 ... Measurement data memory, 24 ... EVM calculation part, 25 ... Phase error calculation part, 26 ... Origin offset calculation part, 27 ... Vector translation calculation part, 28 ... Vector rotational movement calculation unit, 30 ... measurement point, 31 ... constellation, 32 ... modulation method, 33 ... ideal point, 34 ... distance between origins, 35, 36, 37 ... vector, 38 ... editing part, 40 ... operation part, 41 ... Display control unit, 42 ... display, 43 and 43a, 43 b, 43c ... edit constellation, 44 ... measurement list, 45 ... circular coordinates

Claims (5)

In the modulation signal analyzing apparatus for analyzing the input modulation signal (a) and displaying the analysis result on the display (42),
An input processing unit (10) for orthogonally demodulating the input modulated signal into I and Q symbol data in symbol units;
A constellation calculation unit (18) for calculating a constellation (31) representing I and Q symbol data at each symbol position sequentially output from the input processing unit as measurement points (30) on IQ coordinates;
A modulation method determination unit (21) for determining the modulation method of the modulation signal from the constellation at each symbol position calculated by the constellation calculation unit;
An ideal point calculation unit (22) for calculating each ideal point (33) of the constellation from the modulation method determined by the modulation method determination unit and the signal level of the I and Q symbol data;
An EVM calculation unit (24) for calculating a vector (35) for connecting each measurement point on the IQ coordinates and each corresponding ideal point;
A vector translation calculation unit (27) that translates the vector at each measurement point calculated by the EVM calculation unit so that the ideal point side end of the vector is located at the origin on the IQ coordinates;
A modulation signal analyzing apparatus comprising: a display control unit (41) for displaying each vector on the IQ coordinates translated by the vector translation calculation unit on the display.   2. The display control unit displays the circular coordinates (45) centering on the origin and having a modulation error rate in a radial direction on the IQ coordinates displayed on the display unit. The modulation signal analysis apparatus described. In the modulation signal analyzing apparatus for analyzing the input modulation signal (a) and displaying the analysis result on the display (42),
An input processing unit (10) for orthogonally demodulating the input modulated signal into I and Q symbol data in symbol units;
A constellation calculation unit (18) for calculating a constellation (31) representing I and Q symbol data at each symbol position sequentially output from the input processing unit as measurement points (30) on IQ coordinates;
A modulation method determination unit (21) for determining the modulation method of the modulation signal from the constellation at each symbol position calculated by the constellation calculation unit;
An ideal point calculation unit (22) for calculating each ideal point (33) of the constellation from the modulation method determined by the modulation method determination unit and the signal level of the I and Q symbol data;
An EVM calculation unit (24) for calculating a vector (35) for connecting each measurement point on the IQ coordinates and each corresponding ideal point;
A phase error calculation unit (25) for calculating a phase error (φ) for each ideal point corresponding to each measurement point calculated by the EVM calculation unit;
The calculated vector of each measurement point is positioned with the ideal point side end of the corresponding vector at the origin on the IQ coordinate, and the direction of the other end of the corresponding vector is determined on the IQ coordinate. A vector rotation movement calculation unit (28) that rotates in a direction away from the reference direction by the calculated phase error;
A modulation signal analyzing apparatus comprising: a display control unit (41) for displaying each vector on the IQ coordinates rotated and moved by the vector rotational movement calculating unit on the display.   The display control unit displays and outputs the vector of each measurement point on the IQ coordinate that has been translated or rotated to the display unit so that the generation time can be identified between the measurement points. The modulation signal analyzing apparatus according to any one of claims 1 to 3. An origin-to-origin distance calculation unit (26) that calculates an inter-origin distance that is a distance to the origin on the IQ coordinates at each ideal point calculated by the ideal point calculation unit;
The display control unit can identify the vector of each measurement point on the IQ coordinate that has been translated or rotated in accordance with the distance between the origins of the ideal points corresponding to each measurement point. 4. The modulation signal analysis apparatus according to claim 1, wherein the modulation signal analysis apparatus outputs the display.

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