JP2001285216A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver that can accurately tune a pre-selector even to a modulation signal the frequency at a peak level of which is fluctuated as time elapses. SOLUTION: In the case of tuning to a peak of a pass band of a YTF 2, an input vale when an integral value of power (or average power) takes a peak is calculated from a distribution of the integral value (or average power) of the power with respect to each input value set to a 2nd digital/analog converter 12b, and the tuning frequency of the YTF 2 is controlled on the basis of the calculated input value. In the case of tuning to a center of the pass band of the YTF 2, the tuning frequency of the YTF 2 is controlled on the basis of an intermediate value between input values at two points at which the level is decreased by 3 dB or 6 dB from the input value when the calculated integral value (or average power) of the power takes a peak.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, W-CDM.
The present invention relates to a receiving apparatus that can accurately tune and receive an input signal of a modulated wave such as A.

[0002]

2. Description of the Related Art A signal analyzer (spectrum analyzer) for analyzing and analyzing a signal to be measured input from the outside and displaying a spectrum includes a source signal (measurement signal) and a cause such as an image response. In order to prevent unnecessary reception of unnecessary signals, the input circuit is provided with a YTF which is a tunable bandpass filter (preselector). FIG. 3 shows the basic configuration of this type of signal analyzer.

In the signal analyzer 21 shown in FIG. 3, a signal to be measured input from an input terminal 22 passes through a YTF 23 as a preselector, and then a signal mixer (mixer) 24.
Is mixed with the signal from the local oscillator 25 and converted into an intermediate frequency signal (IF signal). The IF signal is subjected to band limitation by the IF filter 26 and then detected by the detector 27, and the detection output is input to the display unit 28 as a vertical axis signal. As the horizontal axis signal of the display unit 28, the output signal of the sweep signal generator 29 is input. As a result, the magnitude (intensity) of each frequency component included in the signal under measurement is displayed on the display 28 in the frequency domain with the horizontal axis representing frequency and the vertical axis representing amplitude.

The frequency of the local oscillator 25 is fixed,
The time variation of the frequency spectrum at that time can also be observed. In this case, the display screen of the display 28 is displayed in the time domain (the horizontal axis represents time, and the vertical axis represents amplitude). Whether to measure in the frequency domain or the time domain is determined by setting conditions from the display panel.

[0005] The YTF 23 as a preselector is an element that performs magnetic resonance in a microwave frequency band.
rium Iron Garnet) This is a sweep bandpass filter that utilizes the characteristic that the resonant frequency changes linearly when the DC magnetic field of a single crystal is changed linearly.

When observing the waveform of a signal under measurement using the YTF, a tracking error (tuning error) occurs in which the center of the YTF is displaced from the signal under measurement mainly due to the hysteresis of the YTF. There is a problem that a signal loss occurs and the level measurement accuracy is deteriorated.

In order to solve this problem, conventionally, the following two methods have been adopted. When performing the pre-selector tuning function in the frequency domain, when the pre-selector tuning function is executed, the signal under measurement (the signal to be tuned by the pre-selector) displayed on the display 28 is converted to the second signal in the frequency domain state. The value of the D / A of the 1D / A converter 30a is set, the frequency of the start position of the sweep is determined, the drive-in process is performed so as to be the center frequency of the display 28, and the local oscillation frequency corresponding to the signal frequency to be measured is obtained. Is detected. Thereafter, a sweep signal for sweeping a predetermined frequency sweep range centered on the detected local oscillation frequency is sent from the sweep signal generator 29 to the local oscillator 25.
And the YTF 23 and the display 28. This state is a normal sweep in which the center frequency is the signal frequency to be measured that has been driven in by the drive-in process and has a predetermined sweep frequency, and this sweep is performed a predetermined number of times. At this time, the value of D / A of the second D / A converter 30b is changed in a predetermined step for each sweep. This operation changes only the tuning frequency of the YTF for each sweep. When the tuning frequency of the YTF is at the peak of the YTF pass bandwidth, the level of the signal to be displayed displayed is at the peak. The D / A of the second D / A converter 30b that reaches this peak
Of the second D / A converter 3
It was set to 0b for tuning.

On the other hand, when the pre-selector tuning function is performed in the time domain, when the pre-selector tuning function is executed, the first D / A converter 3 remains in the time domain state.
The D / A value of 0a is set to determine the frequency at the start position of the sweep, and the signal to be measured (the signal to be tuned by the preselector) displayed on the display 28 is set to the center frequency of the display 28. As a result, the local oscillation frequency corresponding to the signal frequency to be measured is detected. Thereafter, the detected local oscillation frequency is set in the local oscillator 25, the reception frequency corresponding to the detected local oscillation frequency is set in the YTF 23, and the sweep signal from the sweep signal generator 29 is displayed on the display 28.
The normal time domain sweep sent only to the target is performed a predetermined number of times. At this time, the D of the second D / A converter 30b is
The value of / A is changed in a predetermined step. This behavior is
This means that only the tuning frequency of the YTF 23 is changed for each sweep. When the tuning frequency of the YTF 23 is at the peak of the YTF pass bandwidth, the level of the signal under measurement displayed is at the peak. The D / A of the second D / A converter 30b that reaches this peak
The value is set in the second D / A converter 30b and the tuning is performed in the same manner as when the pre-selector tuning is performed in the frequency domain.

However, the above-mentioned method is effective only for a CW signal whose peak level frequency of a signal under measurement does not change with time.

[0010]

However, in recent years,
CDMA (Code Division Multi)
A modulation signal such as a ple access) method or a wideband CDMA (M-CDMA) is used.
Unlike the W signal, the frequency of the peak level fluctuates arbitrarily with time. For this reason, when performing the signal analysis by measuring the modulation signal by the above-described conventional method of detecting the peak level, the YTF cannot be accurately tuned to the modulation signal whose peak level frequency fluctuates. Erroneous measurement may be performed.

In view of the above, the present invention has been made in view of the above problems, and provides a preselector tuning apparatus and a signal analysis apparatus which can accurately tune a modulated signal such as CDMA. It is intended to be.

[0012]

In order to achieve the above object, the invention according to claim 1 comprises a preselector 2 comprising a band-pass filter for selecting an input signal capable of sweeping a tuning frequency; A frequency converter 15 having a possible local oscillator 3 for mixing with an output from the preselector and converting it to an intermediate frequency signal; a detector 7 for receiving and detecting and outputting the intermediate frequency signal; An A / D converter 8 for converting the output of the device into digital data, a sweep unit 4 for transmitting a sweep signal for sweeping the tuning frequency of the preselector and the output frequency of the local oscillator for a predetermined sweep time, A control signal generator 12 that outputs a preselector control signal for controlling the preselector in addition to a sweep signal sent from the sweeper to the preselector; The value of the pre-selector control signal is changed for each sweep, and the control voltage and power characteristics of the pre-selector control signal during the sweep time are calculated from digital data output by the A / D converter for each sweep. And a measurement control unit 11 that determines a value of a pre-selector control signal from at least one point of the power value of the characteristic and outputs a pre-selector control signal of the determined value to the control signal generation unit during measurement. An input signal is received by the preselector controlled by a signal obtained by adding a preselector control signal of the determined value to a sweep signal from the sweep unit.

According to a second aspect of the present invention, in the receiving apparatus of the first aspect, the power value is an integrated value in a sweep time.

According to a third aspect of the present invention, in the receiving apparatus of the first aspect, the power value is an average value in a sweep time.

According to a fourth aspect of the present invention, in the receiving apparatus of the first aspect, the measurement control section 11 causes the sweeping section 4 to sweep the set desired receiving frequency range.

According to a fifth aspect of the present invention, in the receiving apparatus according to the first aspect, the measurement control section 11 controls the sweep section (4) so as to maintain a set desired reception frequency at one point during the sweep time. Is controlled.

According to a sixth aspect of the present invention, in the receiving apparatus of the first aspect, the measurement control section 11 determines the value of the preselector control signal such that the characteristic value becomes the maximum value of the characteristic value distribution. Features.

According to a seventh aspect of the present invention, in the receiving apparatus according to the first aspect, the measurement control section 11 determines a middle point between two points indicating a value lower than the maximum value of the characteristic value distribution by a predetermined value. Is determined as the value of.

[0019] The invention of claim 8 is the reception apparatus of claim 1, wherein the spectrum of the input signal is analyzed based on the digital data.

[0020]

FIG. 1 is a block diagram of a signal analyzer including a preselector tuning device according to the present invention, and FIG. 2 is a diagram for explaining a procedure for obtaining a set value of D / A during tuning.

The signal analyzer 1 of this embodiment comprises a YTF 2, a local oscillator 3, a sweeper 4, a signal mixer 5, an IF filter 6,
Detector 7, A / D converter 8, storage unit (waveform memory) 9,
Display unit 10, measurement control unit 11, first D / A converter 12a
D / A conversion unit 12 as a control signal generation unit including a D / A converter 12b, an addition unit 13, and a V / I conversion unit 14.
It is schematically constituted by Note that the local oscillator 3, the signal mixer 5, and the IF filter 6 constitute a frequency conversion unit 15 that converts a signal to be measured input from the outside into an intermediate frequency signal and limits the band.

As described above, YTF2 as a preselector is an element that magnetically resonates in a microwave frequency band, and a frequency that resonates when the DC magnetic field of a YIG (Yttrium Iron Garnet) single crystal is linearly changed. Is a sweep bandpass filter using the characteristic of changing linearly.

In the frequency domain state, the local oscillator 3 sweeps the oscillation frequency over a predetermined frequency range by the sweep signal from the sweep signal generator 4 (frequency sweep).
Is done. On the other hand, in the time domain state, the sweep signal from the sweep unit 4 is not sent to the local oscillator 3, and the local oscillator 3 is set to a fixed oscillation frequency.

The sweep unit 4 applies YTF2 to the signal under measurement.
When the pre-selector automatic tuning function for automatically tuning is performed, a sweep signal (voltage signal) for sweeping the tuning frequency of the YTF 2 and the output frequency of the local oscillator 3 for a predetermined sweep time is output from the YTF 2 and the local oscillator 3. Output to each.

More specifically, in the frequency domain state, the sweeping unit 4 inputs a sweep signal to the local oscillator 3 so as to sweep the oscillation frequency of the local oscillator 3 over a predetermined frequency range, and adjusts the oscillation frequency of the local oscillator 3. It is variable. On the other hand, in the time domain state, the oscillation frequency of the local oscillator 3 is set so that the oscillation frequency of the local oscillator 3 is fixed. At the same time, the sweep unit 4
The sweep signal is input to the first adder 13a of the adder 13.

The signal mixer 5 mixes the signal passing through the YTF 2 with the oscillation frequency from the local oscillator 3, converts the signal into an intermediate frequency signal (IF signal), and inputs the signal to the IF filter 6. IF filter 6 composed of a band pass filter
In the above, the IF signal from the signal mixer 5 is band-limited to a predetermined frequency width and passed. The detector 7 receives and detects the intermediate frequency signal that has passed through the IF filter 6, and performs A / D
It is output to the converter 8.

The A / D converter 8 converts the signal detected by the detector 7 into digital data. The storage unit 9 stores A /
The digital data (waveform data) converted by the D converter 8 is stored. When the input value of the second D / A converter 12b of the D / A converter 12 is changed for each sweep in the calibration mode by the automatic preselector tuning function, the storage unit 9 stores the second D / A in the sweep time. / A converter 12
The power value for each input value b is stored as digital data.

Digital data (power value) stored in the storage unit 9 is input to the display unit 10 as a vertical axis signal, and a sweep signal of the sweep unit 4 is input as a horizontal axis signal. That is, in the display unit 10, in the frequency domain state,
The horizontal axis on the display screen is a frequency scale, and the vertical axis is a waveform with the magnitude (intensity) of each frequency component included in the signal under measurement. In the time domain state, the display unit 10 sets the horizontal axis on the display screen as a time scale,
The vertical axis represents the waveform as the magnitude of the frequency component included in the signal under measurement.

The measurement control section 11 is provided with setting means 11a, integrated value / average value calculation means 11b, peak detection means 11c, intermediate value calculation means 11d, and YTF control means 11e. The part related to the calculation and control of the measurement control unit 11 can be realized by a microprocessor such as a CPU, for example.

Although not shown, the setting means 11a displays a setting screen displayed on the display unit 10 on the setting screen, the frequency value at the start position of the sweep, the reception frequency range, the sweep time, the reception frequency at one point, etc. Setting, whether to execute the pre-selector tuning function, and YT
Settings are made to select whether to tune to the peak of the pass band of F2 or the center of the pass band of YTF2.

The integrated value / average value calculation means 11b is a YTF
2, the value of the preselector control signal is changed for each sweep of the sweep unit 4, and the characteristic value in the sweep time is calculated from the digital data output from the A / D converter 8 for each sweep. Here, the characteristic value is an integrated value during the sweep time or an average value during the sweep time.

More specifically, in the frequency domain state, the integrated value / average value calculating means 11b determines the input value (control voltage value) α of the second D / A converter 12b of the D / A converter 12 in a predetermined step. When variably controlled, the signal is detected by the detector 7 in the frequency sweep range for each sweep, and is stored in the storage unit 9.
Is calculated based on the digital data stored in the second D / A converter 12b as shown in FIG.

The integrated value / average value calculating means 11b is
In the time domain state, when the input value (control voltage value) α of the second D / A converter 12b of the D / A converter 12 is variably controlled, the detector 7 is controlled in the time axis sweep range for each sweep.
The distribution of the average power of each input value of the second D / A converter 12b as shown in FIG. 2 is calculated based on the digital data detected and stored in the storage unit 9.

When tuning to the peak of the pass band of YTF2 in the frequency domain state, the peak detecting means 11c is the second D / A converter of the D / A converter 12 calculated by the integrated value / average value calculating means 11b. The input value (control voltage value) α0 at which the integrated value of power reaches a peak is calculated from the distribution of the integrated value of power with respect to each input value (control voltage value) α of 12b.

When the peak detecting means 11c tunes to the peak of the pass band of the YTF2 in the time domain state, the second D / A of the D / A converter 12 calculated by the integrated value / average value calculating means 11b. The input value (control voltage value) α0 at which the average power reaches a peak is calculated from the distribution of the average power for each input value (control voltage value) α of the converter 12b.

When tuning to the center of the pass band of YTF2 in the frequency domain state, the intermediate value calculating means 11d uses the input value α0 obtained by the peak detecting means 11c.
Input value α at 2 points where 3dB or 6dB level drops from
An input value (α1 + α2) / 2, which is an intermediate value between 1 and α2, is calculated as an intermediate control value. This calculation is similarly performed when tuning to the center of the pass band of YTF2 in the time domain state.

When the preselector automatic tuning function is executed, the YTF control means 11e determines the frequency of the sweep start position based on the information (sweep time, sweep start frequency, sweep frequency range) set by the setting means 11a. Control to output control data for determining to the first D / A converter 12a of the D / A conversion unit 12, and the second D / A converter to change the input value of the second D / A converter 12b in a predetermined step. 1
2b, control for outputting control data, and the optimum input value (α or α0 or (α1 +
The second D / A converter 12 outputs an output of α2) / 2).
b to output control data.

The measurement control section 11 controls the sweep section 4 so as to sweep the set desired reception frequency range in the frequency domain state. In the time domain state, the sweep unit 4 is controlled so as to maintain the set desired reception frequency at one point during the sweep time.

The D / A converter 12 is a first D / A converter 1
2a and a second D / A converter 12b. 1D /
The A converter 12a converts the control data for determining the frequency of the sweep start position input from the YTF control unit 11e into a preselector control signal (voltage signal), and
3 to the first adder 13a. The second D / A converter 12b converts the correction data for tuning input from the YTF control unit 11 into a preselector control signal (voltage signal) and outputs the same to the second adder 13b of the adder 13. .

The adder 13 includes a first adder 13a and a second adder 13b. The first adder 13a receives the sweep signal from the sweep signal generator 4 and the first D of the D / A converter 12.
It adds the preselector control signal from the / A converter 12a and outputs the result to the second adder 13b. Second adder 13
b adds the addition signal from the first adder 13a and the preselector control signal from the second D / A converter 12b of the D / A converter 12, and outputs the result to the V / I converter 14.

The V / I converter 14 converts a signal (voltage signal) input from the second adder 13b of the adder 13 into a current signal, and variably controls the tuning frequency of the YTF2 based on the converted current signal. are doing.

Next, the operation of the signal analyzer having the above configuration will be described with reference to FIGS. 1 and 2 for the case of the calibration mode and the case of the measurement mode.

In the calibration mode, a pre-selector tuning function is executed so that the peak of the pass band of the YTF2 is tuned to the frequency of the signal under test, as described below.
The tuning frequency of YTF2 is controlled such that the center of the passband of TF2 is tuned to the frequency of the signal under measurement.

In the calibration mode, the state of the frequency domain for displaying the waveform of the signal under test with the frequency on the horizontal axis and the amplitude on the vertical axis on the display screen of the display unit 8 and the horizontal axis on the display screen of the display unit 8 In the time domain where the waveform of the signal under measurement is displayed with time as the amplitude and the vertical axis as the amplitude. The signal processing procedure in each case will be described.

First, in the state of the frequency domain, when the sweep time, the sweep start frequency, the sweep frequency range and the like are set by the setting means 11a, the first D / A of the D / A converter 12 is set.
Control data corresponding to the sweep start frequency is input from the YTF control means 11e to the converter 12a, and the YTF2 is controlled by the output of the first D / A converter 12a.

On the other hand, the YTF control means 11e forcibly sets the input value of the second D / A converter 12b of the D / A converter 12 in a known range at predetermined steps such as α1, α2,. Change. As a result, the tuning frequency of YTF2 becomes equal to the output of the first D / A converter 12a, the second D / A
The output of the A-converter 12b and the sweep signal of the sweep unit 4 are added to each other, and variably controlled by a signal converted into a current signal.

When the tuning frequency of the YTF 2 is variably controlled as described above, the signal under measurement that has passed through the YTF 2 is detected by the detector 7 via the frequency converter 15, and the A / D converter 8 The converted digital data is stored in the storage unit 9.

As described above, the second D / A converter 12
When the input value of b is variably controlled within a known range, the storage unit 9
Stores digital data in a frequency sweep range for each sweep when the input value α of the second D / A converter 12b is varied from 0 by predetermined steps.

Thereafter, the integrated value / average value calculating means 11b
Calculates an integrated value or an average value of power for each input value α of the second D / A converter 12b based on the digital data stored in the storage unit 9. Next, the input value α is plotted on the horizontal axis, and the integrated value or average value of power is plotted on the vertical axis. This example is shown in FIG. When tuning to the peak of the pass band of YTF2, the peak detecting means 11c
Calculates the input value α0 at which the integrated value of power peaks from the distribution of the integrated value of power for each input value α. When the calibration mode ends and the measurement mode is set, the input value α0
Is output as a control voltage to the second D / A converter 12b by the YTF control means 11e. Thereby, at the time of measurement, the 2D
The input value of the / A converter 12b is set to α0, and then
The operation moves to the measurement mode, and the spectrum of the signal under measurement is analyzed based on the digital data stored in the storage unit 9.

When tuning to the center of the pass band of YTF2, as shown in FIG. 2, the intermediate value (α1 + α2) between the input values α1 and α2 at two points where the input value α0 obtained by the above calculation falls by 3 dB or 6 dB from the input value α0. ) / 2 is calculated by the intermediate value calculating means 11d. When the calibration mode is completed and the measurement mode is set, the input value (α1 + α2) / 2 of the calculated intermediate value is calculated by the YTF control unit 11e in the second D
The control voltage is output to the / A converter 12b. Thus, the input value of the second D / A converter 12b becomes (α1 + α2)
/ 2, and then goes to measurement mode operation,
The spectrum of the signal under measurement is analyzed based on the digital data stored in the storage unit 9.

Next, in the calibration state in the time domain,
When the sweep time, sweep start frequency (measurement frequency) and the like are set by the setting unit 11a (in the case of the time domain,
The measurement frequency is not swept but only one wave, and only the time axis is swept. The time change of the measurement frequency signal is observed), D /
Control data corresponding to the sweep start frequency is input from the YTF control unit 11e to the first D / A converter 12a of the A conversion unit 12, and the input value of the first D / A converter 12a is controlled.

On the other hand, the YTF control means 11e forcibly sets the input value of the second D / A converter 12b of the D / A converter 12 in a known range at predetermined steps such as α1, α2,. Change. As a result, the tuning frequency of YTF2 becomes equal to the output of the first D / A converter 12a, the second D / A
The output of the A converter 12b and the sweep signal of the sweep unit 4 (a fixed value or 0 in the case of the time domain) are added to each other and variably controlled by a signal converted into a current signal.

When the tuning frequency of the YTF 2 is variably controlled as described above, the signal under measurement that has passed through the YTF 2 is detected by the detector 7 via the frequency converter 15, and the A / D converter 8 The converted digital data is stored in the storage unit 9.

As described above, the second D / A converter 12
When the input value of b is variably controlled within a known range, the storage unit 9
Stores digital data of a time-axis sweep range for each sweep when the input value α of the second D / A converter 12b is changed from 0 at predetermined steps.

Thereafter, the integrated value / average value calculating means 11b
Calculates an integrated value or an average value of power for each input value α of the second D / A converter 12b based on the digital data stored in the storage unit 9. Next, the input value α is plotted on the horizontal axis, and the integrated value or average value of power is plotted on the vertical axis. This example is shown in FIG. When tuning to the peak of the pass band of YTF2, the peak detecting means 11c
Calculates the input value α0 at which the average power value reaches a peak from the distribution of the average power value for each input value α. When the calibration mode ends and the measurement mode is set, the input value α0 is set to Y
The TF control unit 11e outputs the control voltage to the second D / A converter 12b. Thereby, at the time of measurement, the second D / A
The input value of the converter 12b is set to α0, and thereafter, the operation shifts to the operation in the measurement mode, and the time change analysis of the spectrum of the signal under measurement is performed based on the digital data stored in the storage unit 9.

When tuning to the center of the pass band of YTF2, as shown in FIG. 2, the intermediate value (α1 + α2) of the input values α1 and α2 at two points where the input value α0 obtained by the above calculation falls by 3 dB or 6 dB from the input value α0. ) / 2 is calculated by the intermediate value calculating means 11d. When the calibration mode is completed and the measurement mode is set, the input value (α1 + α2) / 2 of the calculated intermediate value is calculated by the YTF control unit 11e in the second D
The control voltage is output to the / A converter 12b. Thus, the input value of the second D / A converter 12b becomes (α1 + α2)
/ 2, and then goes to measurement mode operation,
A time change analysis of the spectrum of the signal under measurement is performed based on the digital data stored in the storage unit 9.

Next, when the mode shifts from the above-mentioned calibration mode to the measurement mode, the tuning frequency of the YTF 2 is changed to the peak of the pass band or the pass band by the current signal from the V / I converter 14 based on the setting in the above-mentioned calibration mode. Tuning control is performed at the center of the pass band. Then, the signal under test input from the input terminal 15 in FIG. 1 passes through the YTF 2 and is mixed with a signal from the local oscillator 3 by the signal mixer 5 and converted into an intermediate frequency signal (IF signal). This IF signal is
The band is limited by the filter 6. Thereafter, the signal is detected by the detector 7 and converted into digital data by the A / D converter 8. This digital data is stored in the storage unit 9 as waveform data.
And input as a vertical axis signal of the display unit 10.

The horizontal axis signal of the display section 10 includes the sweep section 4
Is output. In the state of the frequency domain, the display unit 10 displays the magnitude (intensity) of each frequency component included in the signal under measurement on the vertical axis and the horizontal axis on the frequency scale. In the time domain state, the display unit 10 displays the magnitude (intensity) of the measurement frequency component included in the signal under measurement on the vertical axis and the horizontal axis on the time scale.

As described above, in the present embodiment, the YTF2
When tuning to the peak of the pass band of the second D / A
From the distribution of the integrated power value (or average power) for each input value set in the converter 12b, an input value at which the integrated power value (or average power) reaches a peak is calculated, and based on the calculated input value It controls the tuning frequency of YTF2.
When tuning to the center of the pass band of YTF2, the integrated value (or average power) of the calculated power drops by 3 dB or 6 dB from the input value at which the peak is reached.
The tuning frequency of YTF2 is controlled based on the intermediate value of the input values of the points. As a result, the preselector can be accurately tuned even for a modulation signal such as W-CDMA in which the frequency of the signal peak level changes over time. Moreover, since it is possible to accurately tune to the center of the pass band of the YTF, it is possible to improve an error in modulation analysis of a frequency band using a preselector.

Although the description has been made with reference to the input value set in the second D / A converter 12b, it can be converted, for example, the output of the second D / A converter 12b or the YT
The configuration described on the basis of the control value direct value of F2 is:
It is within the scope of the present invention.

In the above embodiment, the signal analyzer for analyzing and analyzing a signal to be measured input from the outside and displaying a spectrum has been described as an example. However, the signal analyzer is used for an EMI test apparatus for noise measurement and the like. You can also.

[0062]

As is apparent from the above description, according to the present invention, the preselector can be correctly adjusted even for a signal modulation signal whose peak level frequency fluctuates with time, such as W-CDMA. Can be tuned to.
Moreover, since it is possible to accurately tune to the center of the pass band of the YTF, it is possible to improve an error in modulation analysis of a frequency band using a preselector.

[Brief description of the drawings]

FIG. 1 is a block diagram of a signal analyzer including a preselector tuning device according to the present invention.

FIG. 2 is a diagram for explaining a procedure for obtaining a set value of D / A during tuning;

FIG. 3 is a diagram showing a basic configuration of a signal analyzer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Signal analyzer, 2 ... YTF (preselector), 3 ...
Local oscillator, 4 sweep unit, 7 detector, 8 A / D converter, 11 measurement control unit, 12 D / A conversion unit (control signal generation unit), 15 frequency conversion unit.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 1/16 H04B 1/16 Z 1/26 1/26 C H04J 13/00 H04J 13/00 A F term (Reference) 5J103 AA07 AA31 CB01 DA03 DA04 DA06 DA07 DA18 DA21 DA22 DA33 DA34 DA44 HB02 HC03 HD05 JA04 LA04 LA26 5K020 AA07 DD22 EE04 EE05 FF00 GG16 HH01 HH13 JJ01 NN01 5K022 EE01 EE31 5K042 AA06 BA09BA02BA09BA02BA09BAK12 CC14 CC21 CC25 DD03 DD04 HH03 JJ07

Claims (8)

[Claims] 1. A preselector (2) constituted by a band-pass filter for selecting an input signal whose tuning frequency can be swept, and a local oscillator (3) capable of sweeping a frequency, wherein A frequency conversion unit (15) that mixes the output with the output to convert it to an intermediate frequency signal; a detector (7) that receives and detects and outputs the intermediate frequency signal; and A that converts the output of the detector to digital data / D converter (8); a sweep unit (4) for sending a sweep signal for sweeping a tuning frequency of the preselector and an output frequency of the local oscillator for a predetermined sweep time; A control signal generator (12) for outputting a preselector control signal for controlling the preselector in addition to the sweep signal sent to the preselector; Changing a value for each sweep, calculating a control voltage-to-power characteristic of the preselector control signal during the sweep time from digital data output from the A / D converter for each sweep; A measurement control unit (11) for determining a value of the pre-selector control signal from at least one point of the value, and outputting a pre-selector control signal of the determined value to the control signal generation unit during measurement; A receiving unit that receives an input signal by the preselector controlled by a signal obtained by adding a preselector control signal of the determined value to a sweep signal from a unit. 2. The receiving apparatus according to claim 1, wherein the power value is an integrated value during a sweep time. 3. The receiving apparatus according to claim 1, wherein the power value is an average value during a sweep time. 4. The receiving apparatus according to claim 1, wherein said measurement control section causes said sweep section to sweep a set desired reception frequency range. 5. The receiving apparatus according to claim 1, wherein the measurement control unit controls the sweep unit to maintain a desired reception frequency at one set point during the sweep time. A receiving device, characterized in that: 6. The receiving apparatus according to claim 1, wherein the measurement control unit determines a value of a preselector control signal such that the characteristic value becomes a maximum value of a characteristic value distribution. Receiver. 7. The receiving apparatus according to claim 1, wherein the measurement control unit sets a middle point between two points indicating a value lower by a predetermined value from a maximum value of the characteristic value distribution as a value of the preselector control signal. A receiving device characterized by determining. 8. The receiving apparatus according to claim 1, wherein a spectrum of the input signal is analyzed based on the digital data.