JP3374154B2 - Spectrum analyzer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectrum analyzer, and in particular, as one measure for statistically evaluating an electromagnetic environment, an amplitude probability distribution (hereinafter referred to as APD) of signal electric field strength of an interference wave or the like. That is, the present invention relates to a spectrum analyzer having a function of effectively displaying a time rate at which the level of an envelope of a signal such as an interfering wave is equal to or higher than a preset threshold value.

[0002]

2. Description of the Related Art In recent years, mobile phones and personal handy phone systems (PH) operated in a frequency band exceeding 1 GHz.
Digital communication such as S) and digital broadcasting are increasing rapidly.

In order to protect these radio services from interfering radio waves, the International Commission on Radio Interference (CISPR), etc.
Interfering wave measurement methods and allowable values are being discussed.

At present, the interference wave allowable value in the frequency band of 1 GHz or less is mainly defined by the quasi-peak value (QP value) of the interference wave.

This is because the QP value of the interfering wave correlates with the degree of obstacle to analog communication.

However, the QP value of the interfering wave or the current CI
It is hard to say that the peak value, which has been discussed as an allowable value in the frequency band of 1 GHz or more in SPR and the like, has a correlation with the degree of obstruction of digital communication and digital broadcasting.

In order to protect digital communication / broadcasting, which is going to be used more and more in the frequency band of 1 GHz or more, from the interference wave, the allowable value of the frequency band of 1 GHz or more is correlated with the degree of failure of the digital system. It is desirable to use a certain index.

On the other hand, the communication quality of a digital communication line is expressed by a bit error rate (BER). Then, the BER deterioration of the digital line caused by the interfering wave is caused by the amplitude probability distribution (APD) of the interfering wave intensity.
It has been reported that it can be estimated from the Probability Distribution).

Therefore, if the APD of the interfering wave intensity can be accurately and easily measured, it is considered to be the most suitable as an index for evaluating the obstacle to the digital communication.

The device for measuring APD of an electric signal has a long history and has been mainly used for measuring static electricity.

With the advance of technology, the APD measuring circuit has been made into a semiconductor and has been speeded up.
The measurement circuit 121 needs the same number of comparators and counters as the number of levels that determine the amplitude resolution.

Therefore, in order to improve the amplitude resolution, it is necessary to add a comparator and a counter in proportion to the number of levels. Therefore, a high resolution APD measuring device becomes expensive and is widely used for EMI measurement and the like. I didn't go to the measuring instrument that was used.

Further, conventionally, a device utilizing a spectrum analyzer has been known as an interfering wave electric field intensity measuring device for statistically evaluating an electromagnetic environment.

FIG. 32 is a block diagram showing a schematic structure of a spectrum analyzer as an interfering wave field intensity measuring device for statistically evaluating this kind of electromagnetic environment.

That is, as shown in FIG. 32 , this spectrum analyzer includes a front end 101, a bandpass filter (BPF) 102, and a log video amplifier (L).
VA) 103, a peak detection circuit 104, a bottom detection circuit 105, a calculation unit 106, and a display device 107.

The front end 101 is a high frequency receiving circuit, and is provided with a frequency converting section including a local oscillator and a mixer for obtaining an intermediate frequency signal (IF).

As a result, the high frequency interference wave or the like received by the antenna (not shown) is output from the front end 101 as its IF signal component, and then the BPF 10 is transmitted.
2, supplied to the peak detection circuit 104 and the bottom detection circuit 105 via the LVA 103.

Here, the peak detection circuit 104 and the bottom detection circuit 105 detect the peak value and the bottom value of the envelope component of the IF signal based on the output from the LVA 103, respectively.

That is, the output signal of the LVA 103 is set to P
(t), the peak value P _p (t _i ) and the bottom value P _b (t _i ) thereof are measured time (t _i ≦ t <t _i +) respectively.
In T),

[0020]

[Equation 1]

Is supplied to the calculation unit 106.

In this calculation unit 106, the peak value P _p in the envelope component of the disturbing wave or the like supplied as described above.
(T _i ), bottom value P _b (t _i ) and front end 1
Based on the front end state number i from 01 or the trigger signal, predetermined arithmetic processing for displaying them on the display device 107 is performed.

FIG. 33 shows a display example on the display device 107 in the spectrum analyzer as described above.

That is, as shown in FIG. 33 , in the display device 107, the peak value P _p (t _i ) and the bottom value P _b (t _i ) in the envelope component such as the interference wave from the calculation unit 106.
And the front end state number i is 0, 1, 2, ..., N _w
It is displayed along the frequency axis by changing in order from -1 (where _Nw is the resolution of the frequency axis).

In this case, f _c on the frequency axis is the center frequency of the measurement range (span), f ₁ is the start frequency, and f ₁ is the start frequency.
₂ is the stop frequency.

Accordingly, from FIG. 33 , the measurement time (t
_i ≤t <t _i + T) received high frequency interference waves, etc.

[0027]

[Equation 2]

The peak value P _p (t _i ) and the bottom value P of
_We can read _b (t _i ) as the analyzed entity on the frequency axis.

In this case, P _p (t _i )>P> P
By displaying the P region of _b (t _i ) by embedding it by hatching, P (t) exists between the peak value P _p (t _i ) and the bottom value P _b (t _i ). It is easy to understand what you are doing.

[0030]

However, in the interference wave field strength measuring apparatus using the spectrum analyzer as described above, the measuring time (t _i ≤t) which is an important factor for statistically evaluating the electromagnetic environment. <T _i +
Since the APD itself based on the output signal P (t) distribution of the LVA 103 in T) is not displayed, there is a problem that the APD is unknown.

It is also possible to display the APD by a contour line display method. However, in this method, as will be described later in detail in comparison with the area identification display method according to the present invention, the contour lines of different thresholds are not overlapped. When it occurs, it is difficult to know which threshold contour line the distribution belongs to.

Therefore, the object of the present invention is, for example, by adopting a region identification display method using a band group having a plurality of layers such as different color bands, thereby causing the problems of the conventional techniques as described above. It is an object of the present invention to provide a spectrum analyzer having a function of solving the above problem and effectively displaying the APD.

Another object of the present invention is to:
For example, by adopting a region identification display method using a band group having a plurality of layers such as different color bands,
An object of the present invention is to provide an APD display method by a spectrum analyzer that solves the above-mentioned problems of the conventional technique and can effectively display the APD.

[0034]

According to the present invention, in order to solve the above-mentioned problems, a signal reception processing means for receiving a signal under measurement according to desired sweep information, and the received signal received by the signal reception processing means. Sampling means for outputting a plurality of output codes corresponding to sample values of the envelope of the signal under measurement by sampling the measurement signal based on a plurality of threshold values, and output by the sampling means. Histogram measurement means for measuring a histogram group corresponding to the plurality of output codes, and an amplitude probability distribution (AP) of the signal under measurement based on the histogram group measured by the histogram measurement means and the desired sweep information.
D) should be calculated and further classified into a band group having a plurality of hierarchies corresponding to the histogram group, and a band group having the plurality of hierarchies calculated by the computing means should be displayed in different states. Display means for displaying as a region , wherein the calculating means is for the amplitude probability
AP comprising means for accumulating and averaging cloth
A spectrum analyzer having a D display function is provided. Further, according to the present invention, in order to solve the above problems
Signal to receive the signal under measurement according to the desired sweep information
Reception processing means and a signal received by the signal reception processing means.
The measured signal under measurement based on a plurality of threshold values
To the sample value of the envelope of the signal under measurement.
A sampling means for outputting a plurality of output codes to respond, the
To the plurality of output codes output by the sampling means
Histogram measurement hand to measure the corresponding histogram group
Step and before measured by the histogram measuring means
Based on the histogram group and the desired sweep information,
The amplitude probability distribution (APD) of the signal under measurement is calculated and
A band having a plurality of layers corresponding to the histogram group
Calculation means for classifying into groups, and calculation means by the calculation means
State that different bands groups each having a plurality of hierarchies
Display means for displaying as an area to be displayed in
However, the calculation means is a function of the amplitude probability distribution.
It includes means for calculating and also calculating its function scale coordinates.
Only the display means displays the band group having the plurality of layers.
When it is displayed as an area that should be displayed in different states
Together, the function scale for the band group having the plurality of layers is
APD display function characterized by including means for displaying
A spectrum analyzer having is provided. Also books
According to the invention, in order to solve the above problems, the signal under measurement is
Signal receiving processing means for receiving the signal according to desired sweep information
And the measured object received by the signal reception processing means.
By sampling a constant signal based on multiple thresholds
A plurality of values corresponding to the sample values of the envelope of the signal under measurement.
Sampling means for outputting an output code, and the sampling means
Therefore, the hiss corresponding to the plurality of output codes output
A histogram measuring means for measuring a chromatogram group, the human
The histogram measured by the strogram measuring means.
Signal to be measured based on the group of groups and the desired sweep information.
The amplitude probability distribution (APD) of the
Classify into a band group having multiple layers corresponding to the gram group
Calculating means and the plurality of pieces calculated by the calculating means
Bands with different levels should be displayed in different states.
Comprising a display means for displaying as come area, the operation manual
The step represents the contour line for the desired value of the amplitude probability distribution.
The display means includes means for calculating to emphasize
Display the band groups having a plurality of layers in different states.
It is displayed as an area to be shown, and the amplitude probability
A hand to highlight the contour lines about the desired value on the cloth
A space having an APD display function characterized by including steps.
A tram analyzer is provided . Also according to the invention
In order to solve the above problems, the measured signal is
Signal reception processing for receiving according to the desired sweep information over the wave number
A management unit, before being received by said signal reception processing unit
The measured signal can be sampled based on multiple thresholds.
Corresponding to the sample value of the envelope of the signal under measurement
Output multiple output codes for each of the multiple frequencies
Force applying sampling means and the sampling means
The output codes corresponding to the plurality of output codes output for each wave number
Histogram measurement to measure the signal at each frequency
Determining means and the histogram measuring means
Multiple histograms measured for each wavenumber and the desired sweep
The amplitude probability distribution (A
PD) is calculated for each frequency, and
Classify into a band group with multiple layers corresponding to
Calculating means, and the compound calculated by the calculating means.
Display bands with several layers in different states
Display means for displaying as a power area,
Spectrum analyzer with characteristic APD display function
Isa is provided.

Further, according to the present invention, in order to solve the above problems, a step of receiving a signal under measurement according to desired sweep information, and a sample of the received signal under measurement based on a plurality of threshold values. By outputting a plurality of output codes corresponding to sample values of the envelope of the signal under measurement, measuring a histogram group corresponding to the plurality of output codes, the histogram group and the desired Calculating an amplitude probability distribution (APD) of the signal under measurement based on the sweep information and further classifying into a band group having a plurality of layers corresponding to the histogram group; and a band group having the plurality of layers. It displayed as areas to be displayed in different respective states and steps
And the plurality of thresholds in the sampling are set in advance.
An APD display method by a spectrum analyzer is provided, which further comprises a step of calibrating . Further, according to the present invention, in order to solve the above problems
The step of receiving the signal under test according to the desired sweep information.
And a plurality of thresholds for the received measured signal.
By sampling based on the value,
Output multiple output codes corresponding to envelope sample values
Steps and a histogram corresponding to the plurality of output codes
Measuring the ram group, the histograms before and
Based on the desired sweep information, the amplitude of the measured signal
A rate distribution (APD) is calculated, and the histogram group
To classify into swaths with multiple layers corresponding to
And different states of the band groups having the plurality of layers.
And a step of displaying as an area to be displayed in
Then, with the function scale calculation for the amplitude probability distribution,
Further comprising the step of calculating the function scale coordinates, before
In the step of displaying, the band group having the plurality of layers is displayed.
Display as areas that should be displayed in different states
Together with a function rule for the band group having the plurality of layers
Is displayed on the spectrum analyzer characterized by
An APD display method according to the present invention is provided . Also according to the invention
In order to solve the above problems, the measured signal is
Receiving according to desired sweep information over wave number
And the received signal under measurement to a plurality of threshold values
By sampling based on the envelope of the signal under measurement
Multiple output codes corresponding to line sample values are
And outputting for each frequency of the wave number, out of the plurality
Measure the histogram corresponding to the force code for each frequency.
Setting step and a plurality of measured values for each frequency.
Based on the histogram and the desired sweep information, the
Amplitude probability distribution (APD) of the measurement signal for each frequency
A plurality of values corresponding to the plurality of histograms
And a step of classifying into a group of bands having a hierarchy of
Belts with layers should be displayed in different states
A step of displaying as an area,
Providing an APD display method using a spectrum analyzer
Be served.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a spectrum analyzer according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment to which a spectrum analyzer according to the present invention is applied.

That is, as shown in FIG. 1, this spectrum analyzer includes a front end 201, a band pass filter (BPF) 202, a log video amplifier (LV).
A) 203, analog-to-digital converter (ADC) 20
4, sampling clock generator 205, histogram measurement circuit 206 including RAM 207, operation unit 208, display device 209, control unit 210, operation unit 211, and display control unit 2
It is configured with 12.

FIG. 2 shows the front end 20 of FIG.
2 is a block diagram showing a detailed configuration of No. 1.

That is, as shown in FIG. 2, the front end 201 includes the first and second BPFs (1, 2) 2
01a, 201d, first and second amplification units 201b, 2
01e, first and second mixers 201c and 201f, first and second local oscillators 201h and 201i, and a local oscillator control circuit 201g.

The front end 201 intermediates the high frequency input f _RF based on a predetermined sweep command, which will be described later, supplied to the local oscillator control circuit 201g from the operation unit 211 of FIG. 1 via the control unit 210. The frequency signal f _IF is converted and output.

In this case, the first and second local oscillators 20
The first and second local oscillator signals from 1h and 201i are f _L1 ,
When f _L2

[0043]

[Equation 3]

The relationship of is satisfied.

The local oscillator control circuit 201g outputs a front end state number i or a trigger signal corresponding to the sweep command to the arithmetic unit 208.

As described above, the front end 201 is a down converter for converting the signal of the reception frequency of f _RF into the signal of the intermediate frequency of f _IF .

Here, f _RF and f _IF are integers.

Therefore, the impulse response of the IF filter and the signal input to the RF input terminal are respectively

[0049]

[Equation 4]

Then, the log video amplifier (LVA) 2
The voltage at the input terminal of 03 is

[0051]

[Equation 5]

It becomes

Here, x * h _B means a convolution integral represented by the following equation.

[0054]

[Equation 6]

Means

Then, the log video amplifier (LVA) 20
3 is

[0057]

[Equation 7]

Is output.

Where | y (t) | is a log amplifier (LV
A) The envelope of the input of 203.

Ξ (r) is a function of the real value r and is a monotonically increasing function. Normal

[0061]

[Equation 8]

It is

The front end 201 includes variable or fixed local oscillators 201h and 201i and has a function of sweeping f _RF .

The front end 201 outputs the front end state number i or the trigger signal indicating the state of the local oscillators 201h and 201i as described above.

Here, a list of symbols used in the specification and drawings of the present invention will be described. Re {x (t)}: RF input signal, x (t) means complex number, t means time, and Re means real part.

Re {y (t)}: BPF output signal = log video amplifier input signal, y (t) is a complex number,

[0067]

[Equation 9]

P (t): log video amplifier output signal (real number), as described above,

[0069]

[Equation 10]

It is represented by

Here, ξ is a monotonically increasing function.

M (k): ADC output code, 0, 1,
2, ..., M-1 values, k is the sample number

[0073]

[Equation 11]

It is represented by

Here, t _A is the sampling start time.

H (m): contents (data) of the RAM 207 at the address m, expressed by the following equation

[0077]

[Equation 12]

It is represented by

W _D : Bit width of RAM (207) data a: Effective value amplitude of RF input f _RF : Reception frequency

[0080]

[Equation 13]

F ₁ : sweep start frequency f ₂ : end frequency i ₀ : frequency axis (time axis) marker position

[0082]

[Equation 14]

D _j : Color band boundary value f _IF : IF filter (BPF) nominal center frequency f _L1 , f _L2 : Frequency of first and second local oscillation N _w : X-axis resolution Display dots per unit span Number T _w : sweep time T _p : dwell time (time when f _RF is constant) q: {0, 1, 2, ..., N _w -1} to {0, 1, 2,
, N _w -1}, which means a function (replacement) that one-to-one is mapped to.

Ω = {0, 1, 2, ..., M-1} ADC
Output code set

[0085]

[Equation 15]

[0086]

[Equation 16]

It is represented by here,

[0088]

[Equation 17]

[0089]

[Equation 18]

Here, APD is the measurement time T from the measurement start time t _i to the measurement end time t _i + T,
r (t) ≧ R, which is APD (R)
, R is an amplitude threshold and has the dimension of the effective voltage.

[0091] g (a): a function for example of the function scale display of the ^{_{Y-axis, 10 log 10 (a 2 /}} 1mW), 20 log 10 (a / 1μ
V) ... η _X (a): monotonically decreasing function of a, 0 ≦ η _X (a) ≦ 1 η _X ⁻¹ (d): inverse function of η _X 0 <d <1

[0092]

[Formula 19]

[0093]

[Equation 20]

Means the largest integer not exceeding x, for example

[0095]

[Equation 21]

It becomes

T _s : sampling period t ₀ : sweep start time j: number indicating color of color band j: APD value 0 ≦ d ≦ 1 FIGS. 3 to 7 show different sweep modes of the front end 201. ing.

When the front end 201 frequency sweeps f _RF , it starts from f _RF = f ₁ at time t ₀ and ends at f _RF = f ₂ at time t ₀ + T _w .

Here, f ₁ <f ₂ , where f ₁ is the start frequency, f ₂ is the stop frequency, T _w is the sweep time, and t is
₀ is called the sweep start time.

The front end 201 selects all or a part of continuous sweep, temporary non-stop sequential sweep, temporary non-stop random sweep, and zero span sweep as a method for frequency sweeping the reception frequency as shown in FIGS. 3 to 7. At the same time, these are automatically repeated for each request from the operation unit 211 or by the control unit 210.

(1) Continuous sweep: The reception frequency f _RF (t) at time t is as follows (see FIG. 3).

[0102]

[Equation 22]

Then, when t = t _0, a trigger signal is issued.

(2) Temporary stop sequential sweep: (See FIG. 4)

[0105]

[Equation 23]

And the state number

[0107]

[Equation 24]

Emits.

Specific reception frequency

[0110]

[Equation 25]

The time T _{p staying} at is less than T _w / N _w .

(3) Zero-span sweep: The reception frequency is constant as shown in the following equation, and frequency sweep is not performed (see FIG. 5).

[0113]

[Equation 26]

In the state number i, the local oscillator is stable (i = 1)
Is being performed or is in a transient state (i = 0) (unstable).

(4) Temporary suspension random sweep: q is {0,
Let 1, 2, ..., N _w -1} be a function (permutation) that one-to-one maps to itself. Let q ^-1 be its reverse image. q ^-1 (q
(i)) = i.

For example, q (i) = (i + i ₀ ) mod N _w is a permutation.

[0117]

[Equation 27]

Then, as the state number

[0119]

[Equation 28]

Emits.

When repeating the sweep, a method of repeating without changing q (see FIG. 6) and a method of changing q by repeating, for example, (i + i ₀ ) mod N _w and changing i ₀ for each repetition are available. Yes (see FIG. 7).

Next, the ADC 204 converts the input P (t) from the log video amplifier (LVA) 203 into m (k) shown in the following expression as an integer value sample.

[0123]

[Equation 29]

Where k is the sample number, T _s is the sampling period,
t _A is the time when the code of sample number 0 is output from the ADC 204, and Δ is the quantization step.

[0125]

[Equation 30]

It is assumed that

For example, in the 8-bit ADC 204, M = 2 ⁸ .

FIG. 8 shows the relationship between the threshold value and the output code in the ADC 204. That is, when the output code is m, the effective value amplitude a of cw (continuous wave) is

[0129]

[Equation 31]

It is in the range of.

Next, the i-th histogram measurement by the histogram measurement circuit 206 is performed as follows.

K _i sample strings

[0133]

[Equation 32]

The histogram of is defined by the following equation.

[0135]

[Expression 33]

[0136]

[Equation 34]

It is

[0138]

[Equation 35]

Now, the frequency f _RF (H
z), cw (continuous wave) of amplitude aV _RMS

[0140]

[Equation 36]

[0141] Enter the front end 201, when gradually increasing a, the output of ADC204 to a threshold value which changes m + 1 and a (m) V _RMS from m.

However, f _RF is RB at the front end 201.
It is the measurement center frequency converted into the center frequency of the W filter 203.

The relation between the threshold values a (m) and a (m + 1) is

[0144]

[Equation 37]

It is assumed that

Incidentally, in the case of FIG. 9, the input of the LVA 203 is

[0147]

[Equation 38]

Therefore, the output of the LVA 203 is as described above.

[0149]

[Formula 39]

It is

Where ξ (a) is a monotonically increasing function, eg
ξ (a) = ln a.

Further, the output code m from the ADC 204
(k) is as described above

[0153]

[Formula 40]

It is represented by

In the expression representing m (k),

[0156]

[Formula 41]

Then, as described above,

[0158]

[Equation 42]

Means the largest integer not exceeding X, for example,

[0160]

[Equation 43]

It is

[0162]

[Equation 44]

Next, a specific example of the histogram measuring circuit 206 will be described.

FIG. 10 is a block diagram showing a concrete example of the histogram measuring circuit 206 in FIG.

11 (a), (b) and (c) are shown in FIG.
6 is a timing chart illustrating the operation of the histogram measurement circuit 206 based on 0.

That is, as shown in FIG. 10, the histogram measuring circuit 206 includes switches S1 and S2 for switching between a histogram measuring state (increment: inc.) And a measurement result output state (dump: dump), and an adder. (ADD) 206a, register 206b, RAM 20
7 and interface circuit 206c.

Here, the address of the RAM 207 in the increment (inc.) State is m (k).

The RAM 207 outputs the data designated by the address input A = m (k) at the rising edge of the clock to the 0 port and holds it until the next rising edge of the clock.

At this time, the data output from the RAM 207 is h (m (k)) as shown in FIG. 11B, and the adder 206a adds 1 to this data.

As a result, h is stored in the register 206b.
(M (k)) + 1 is input.

At the rising edge of the 1 / T _s Hz clock, this data is transferred to the output of register 206b.

Therefore, from the register 206b, as shown in FIG.
Immediately before this edge, as shown in (c) of FIG.
−1)) + 1 and immediately after that, h (m (k)) + 1 is output.

As a result, the data immediately before this edge is written in the RAM 207.

At this time, the read (R) and write (W) state control of the RAM 207 is performed at clocks 1 and 0 as shown in FIG.

Dump state: In this state,
The clock is fixed at the 1 state.

Then, the switches S1 and S2 are set to the dump side, and the address is given from the interface circuit 206c.

[0177]

[Equation 45]

FIG. 12 shows the timing relationship between the inc state and the dump state.

Now, at time t, as shown in FIG.

[0180]

[Equation 46]

If it is in the inc state for the range of,
(K _i ), m (k _i +1), m (k _i +2), ..., M
After the (k _i + K _i ) sample is input to the histogram measurement circuit 206, the result of reading the data from the RAM 207 in the dump state is as follows.

[0182]

[Equation 47]

In this way, inc, dump, in
If c and dump are repeatedly measured and the duration of each inc state is less than 2 ^{W D} T _s

[0184]

[Equation 48]

Because it is

[0186]

[Equation 49]

In FIG. 12, the time relationship is

[0188]

[Equation 50]

It is

Here, T _D is the time in the dump state, T
_READ is a read time (approximately 25 nsec), T _WRITE is a write time (approximately 25 nsec), and T _ADD is a +1 addition time (approximately 10).
nsec).

For example, if M = 256, then 6.4 μs
ec <T _D.

Next, the calculation operation of the color band display by the calculation unit 208 will be described.

[0193]

[Equation 51]

Here, in the APD, the instantaneous amplitude value is within the measurement time.

[0195]

[Equation 52]

It is assumed to represent a time rate exceeding the above.

[0197]

[Equation 53]

However,

[0199]

[Equation 54]

It is

FIG. 13 shows how the output of the ADC 204 is calibrated in advance.

That is, at the time of calibration, the RF input end of the front end 201 is set under the zero span sweep of f _RF.

[0203]

[Equation 55]

[0204]

[Equation 56]

It is assumed that

Here, the function scale will be described. The vertical axis of the function scale is amplitude, and dB _μV = 20 log.
₁₀ (a / 1 μV) or dB _m or dB or V or W is selected and graduated so that they are evenly spaced.

Also, the horizontal axis of the function scale is the time rate,
Scale with <d <1 or this% value.

[0208]

[Equation 57]

[0209] is plotted, and the space between the plotted points is complemented.

In FIG. 14, P _X is a Rayleigh distribution and g (x) =
This is an example in the case of 20 log ₁₀ (x), and becomes a straight line when the RF input is thermal noise.

Next, the display using the above-described function scale will be described.

First,

[0213]

[Equation 58]

There are various types, and a menu format can be selected from the Rayleigh distribution, the normal distribution, the exponential distribution, the x ² distribution, etc. by the operation unit 211 and the display device 209.

In addition,

[0216]

[Equation 59]

Is a monotonically decreasing function, and there exists an inverse function η _X ^-1 .

In this case, 0 <η _X (X) ≦ 1.

G is a monotonically increasing function,

[0220]

[Equation 60]

It can be selected from the following.

For example, in the case of Rayleigh distribution

[0223]

[Equation 61]

[0224]

Here

[0226]

[Equation 62]

In case of

[0228]

[Equation 63]

[0229]

However, it is assumed that exp (x) = e ^x .

FIG. 15 is a graph showing this relationship.

That is, as shown in FIG. 15, this graph becomes a straight line when the RF input to the front end 201 is thermal noise, so it is possible to discriminate between thermal noise and other noise.

Next, an example of how to make a function rule will be described.

[0234]

[Equation 64]

Here, P _X (x) is the probability density function (PDF) of the random variable x.

[0236]

[Equation 65]

Here, it is assumed that g is a monotonically increasing function and there exists an inverse function g ⁻¹ (Y).

Now, assuming that y ₀ = g (x ₀ ), obviously

[Equation 66]

It becomes:

Therefore, when 0 <d <1, x ₀ = η _X
^-1 (d) exists.

In addition,

[0242]

[Equation 67]

It is.

Therefore,

[0245]

[Equation 68]

It is.

For example, in the case of Rayleigh distribution

[0248]

[Equation 69]

That is.

Here,

[0251]

[Equation 70]

In case of

[Equation 71]

That is.

And, d is 0.99, 0.9, 0.5, 0.1, 0.0
When 1, 0.001, 0.0001, 0.00001, η _Y ^-1 (d) = 10
log ₁₀ (-2lnd) is -17, -6.7, 1.4, 6.6, 9.6, respectively
11.4, 12.7, 13.6, 4.05 × {η _Y ^-1 (d) -1.4}
Are -74.5, 32.8, 0,21.1, 33.2, 40.5, 45.8, respectively.
49.5.

By the way, the thermal noise envelope r (t) has a Rayleigh distribution.

Therefore, when P _rob (r (t) ≧ A) = d is plotted on this function scale graph, the plot points are arranged linearly.

That is, the coordinates η _Y ⁻¹ (P _rob (r ≧
A)), to score 20 log ₁₀ A is P _rod (r ≧
A) = d plot.

FIG. 16 shows an example of a function scale graph.

That is, in this function scale graph, the vertical axis (horizontal line) of the dB scale, d _i = 0.99, 0.9, 0.5, 0.1, 0.
Η _Y ^-1 (d when 01, 0.001, 0.0001, 0.00001
_i ) is made up of a horizontal axis consisting of vertical lines.

When the horizontal axis is expressed in mm with d ₀ = 0.5 as a reference, the horizontal coordinate is 40.5 log ₁₀ (−2 lnd) −5.7 mm.

That is, FIG. 16 shows A of the thermal noise envelope A.
For PD, 20 log ₁₀ A (vertical axis), η _Y ^-1 (d) = 10
An example of a function scale graph when log ₁₀ (−2 lnd) (horizontal axis) is shown.

Next, display by cumulative calculation will be described.

The APDs acquired in each sweep can be displayed after being accumulated.

[0264]

[Equation 72]

However, N _w <(T _w / T _s ) / K, K
_i <K

In the random sweep described above,

[0267]

[Equation 73]

It is.

In the zero span sweep described above, j _{i + 1}
Specify> j _i

[0270]

[Equation 74]

Is displayed.

At this time, the horizontal axis represents T _s kj i or T _s k
j i + 1 or the average value of the former two.

[0273]

[Equation 75]

It should be noted that f (i) is the reception frequency f _RF for i except for the zero span sweep.

At the time of zero span sweep, it is the elapsed time from the measurement start point.

[0276]

[Equation 76]

Or

[0278]

[Equation 77]

Or

[0280]

[Equation 78]

That is.

[0282]

[Equation 79]

It can be read as "."

FIG. 17 shows an example of a color band display screen by cumulative calculation.

However, the number i shown on the lower side in FIG. 17 is not displayed on the actual screen.

Next, a method of generating a color band will be described.

Let J + 2 be the number of color bands, and d ₀ = 1,
Let d _J = 0.

Boundary value of color band 0 <d _J-1 <d _J-2 <... <d
₂ <d ₁ <1 shall be designated in advance, but this designation is arbitrary.

(1) Generation of color band J + 1 The peak boundary value is determined as follows.

[0290]

[Equation 80]

And

[0292]

[Equation 81]

(2) Generation of color band 0

[0294]

[Equation 82]

And

[0296]

[Equation 83]

The color band 0 and the color band J + 1 may be painted in the same color.

(3) Generation of color bands 1, 2, ... J in this case

[0299]

[Equation 84]

FIG. 18 shows an example of color band generation when J = 5.

[0301]

[Equation 85]

In this example, the color band 2 does not occur.

Note that, in FIG. 18, for convenience of description, the color band areas 0, 1, 3, 4, 5, 6 are shown filled in along the horizontal axis. It is the Y axis on the screen.

19 to 22 show an example of color band generation when 6-color display is performed when J = 4.

In each of these figures, (0), (1), ... (5) are areas filled with different colors.

Note that, in FIG. 22 showing the case of displaying the contour lines together with the color band display, the vertical axis scale (a1),
(A2) ... (a19) is not displayed on the actual screen,
On the actual screen, the Y-axis scale displayed in dBm (-7
0 dBm to 0 dBm). Further, in FIG. 22, the scales (a1), (a2) ... (a19) of the vertical shaft do not have to be equidistant.

By the way, in the contour line display, as shown in FIG. 23, contour lines having different threshold values may overlap each other, so that the contour lines cannot be separated.

Even if the contour lines are color-coded, the overlapping portions are not colored and the lines themselves are colored, so that it is difficult to distinguish them from a distance.

That is, in the contour line display, there is a problem that a human cannot intuitively grasp an event and the display is deteriorated when the number of pixels is small.

On the other hand, in the color band display according to the present invention,
As shown in FIG. 24, since the color bands are displayed, there is no overlap so that it is possible to easily identify from a distant place and it is possible to display even when the number of pixels is small.

Further, in the contour display, there is a problem that unnecessary spots S1 and S2 are generated as shown in FIG.

On the other hand, in the color band display according to the present invention,
As shown in FIG. 26, such an unnecessary spot does not occur.

Next, an example in which the color band display and the function scale display described above are displayed on the left and right sides of the same screen will be described.

In this case, the vertical axis is a scale g related to amplitude.
(a) and the horizontal axis is f (i) and g (η _X ^-1 (d)).

As an example, a knob or key (not shown) of the operation unit 211 is used.

[0316]

[Equation 86]

FIG. 27 shows an example of color band and function scale simultaneous display.

In this case, i ₀ <j is specified and

[0319]

[Equation 87]

Or specify i ₀ ,

[0321]

[Equation 88]

[0322]

[Equation 89]

FIG. 28 shows the function scale graph portion.

This function scale graph is

[0325]

[Equation 90]

The function scale η (x) is a monotonically decreasing function of x.

Next, another example of simultaneous display of the color band function scale will be described.

FIG. 29 shows a case where the function band portion is displayed on a plane orthogonal to the plane of the color band display portion as a mode of simultaneous display of the color band function scale according to another example.

In the same manner as described above, 0 <d <1 is designated by the knob or the key.

[0330]

[Formula 91]

30 and 31 are flow charts for explaining the overall operation of the present invention as described above.

That is, as shown in FIGS. 30 and 31, in step ST1, the arithmetic unit 208 receives the front end state number i, and the histogram measuring circuit 206 outputs R
From AM207

[0333]

[Equation 92]

Read out.

Next, in step ST2,

[0336]

[Equation 93]

Histogram calculation is performed based on.

Next, in step ST3,

[0339]

[Equation 94]

The APD calculation is performed based on

Next, in step ST4,

[0342]

[Formula 95]

Cumulative calculation is performed based on.

Next, in step ST5,

[0345]

[Equation 96]

Based on, the function scale calculation is performed.

Next, in step ST6,

[Numerical Expression 97]

The area to be filled in with the color band j is determined based on. j spans all color bands.

Here,

[0350]

[Equation 98]

Is a rectangular area to be filled with the color j.

Next, in step ST8,

[0353]

[Numerical expression 99]

It becomes

[0355]

[Equation 100]

Search for:

Next, in step ST9,

[0358]

[Equation 101]

Then, the process returns to step ST1 and repeats the series of processes described above until the predetermined number of processes is completed.

In the above processing, i ₀ , d,
j, the range of d _j is assumed that the user is determined.

[0361]

[Equation 102]

Is determined at the time of calibration, and its unit is V
It is _RMS .

It is assumed that the user selects g and η _X from the menu.

[0364]

[Equation 103]

[0365]

Therefore, as described above, according to the present invention, for example, by adopting the area identification display method by the band group having a plurality of layers such as different color bands, the problem of the prior art can be solved. spectrum analyzer and having a function of effectively displaying the APD to solve the point
An APD display method using a spectrum analyzer can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment to which a spectrum analyzer according to the present invention is applied.

2 is a block diagram showing a detailed configuration of a front end 201 in FIG.

FIG. 3 is a diagram showing a continuous sweep mode as a sweep state in the front end 201 of FIG.

4 is a diagram showing a temporary non-stop sequential sweep mode as a sweep state in the front end 201 of FIG.

5 is a diagram showing a zero span sweep mode as a sweep state in the front end 201 of FIG.

6] FIG. 6 is a temporary deferred random sweep mode (q: fixed) as a sweep state in the front end 201 of FIG. 1.
FIG.

FIG. 7 is a temporary detained random sweep mode (q: variable) as a sweep state in the front end 201 of FIG. 1.
FIG.

8 is a diagram showing a relationship between a threshold value of the ADC 204 in FIG. 1 and an output code.

FIG. 9 is a diagram for explaining a method of determining a threshold value in ADC 204.

10 is a block diagram showing a specific example of a histogram measuring circuit 206 in FIG.

11 (a), (b), and (c) of FIG.
6 is a timing chart for explaining the operation of the histogram measurement circuit 206 according to the above.

12 is a block diagram of the RAM 207 in FIG.
It is a figure which shows the timing relationship of a c state and a dump state.

FIG. 13 is a diagram showing in advance ADCs 204 in FIG.
FIG. 6 is a diagram showing a state of calibrating the output of FIG.

FIG. 14 shows that P _X is Rayleigh distribution, g (x) = 20
It is a case of log ₁₀ (x), and is a diagram showing an example of a straight line when the RF input is thermal noise.

FIG. 15 is a graph showing a relationship capable of discriminating between thermal noise and noise other than thermal noise, because a straight line is obtained when the RF input is thermal noise.

FIG. 16 is a diagram showing an example of a function scale graph.

FIG. 17 is a diagram showing an example of a color band display screen by cumulative calculation.

FIG. 18 is a diagram illustrating an example of color band generation when J = 5.

FIG. 19 is a diagram illustrating an example of color band generation when performing 6-color display when J = 4.

FIG. 20 is a diagram illustrating an example of color band generation when performing 6-color display when J = 4.

FIG. 21 is a diagram illustrating an example of color band generation when performing 6-color display when J = 4.

FIG. 22 is a diagram illustrating an example of color band generation when performing 6-color display when J = 4.

FIG. 23 is a diagram showing a contour line display according to the related art.
It is a figure which shows that contour lines cannot be separated because contour lines of different threshold values may overlap.

FIG. 24 is a diagram showing that in the color band display according to the present invention, since the color band displays do not overlap each other, it is possible to identify from a distance and to display even when the number of pixels is small.

FIG. 25 is a diagram showing a contour display according to the related art.
It is a figure which shows that unnecessary spots S1 and S2 generate | occur | produce.

FIG. 26 is a diagram showing that in the color band display according to the present invention, unnecessary spots unlike the contour line display are not generated.

FIG. 27 is a diagram showing an example of color band and function scale simultaneous display.

FIG. 28 is a diagram showing a function-scale graph portion.

FIG. 29 is a diagram showing a case where the function scale part is represented on a plane orthogonal to the plane of the color band display part as a mode of simultaneous display of the color band function scale according to another example.

FIG. 30 is a first flow chart for explaining the overall operation according to the present invention.

FIG. 31 is a second flowchart for explaining the overall operation according to the present invention.

FIG. 32 is a block diagram showing a schematic configuration of a spectrum analyzer applied as a conventional interfering wave field intensity measuring apparatus for statistically evaluating an electromagnetic environment.

FIG. 33 is a diagram showing a display example on the display device 107 in the conventional spectrum analyzer.

[Explanation of symbols]

201 ... front end, 202 ... Bandpass filter (BPF), 203 ... Log video amplifier (LVA), 204 ... Analog-to-digital converter (ADC), 205 ... Sampling clock generator, 206 ... Histogram measurement circuit, 207 ... RAM, 208 ... Arithmetic unit, 209 ... Display device, 210 ... control unit, 211 ... Operation unit, 212 ... Display control unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI H04B 17/00 H04B 17/00 R (56) References JP-A-10-170574 (JP, A) JP-A-9-218230 ( JP, A) JP 1-297564 (JP, A) JP 61-28875 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01R 23/16 G01R 23/173 H04B 17/00

Claims (18)

(57) [Claims] 1. A signal reception processing unit for receiving a signal under measurement according to desired sweep information, and sampling the signal under measurement received by the signal reception processing unit based on a plurality of threshold values,
Sampling means for outputting a plurality of output codes corresponding to sample values of the envelope of the signal under measurement, and histogram measuring means for measuring a histogram group corresponding to the plurality of output codes output by the sampling means. , An amplitude probability distribution (APD) of the signal under measurement is calculated based on the histogram group measured by the histogram measuring unit and the desired sweep information, and a band having a plurality of layers corresponding to the histogram group. comprising a calculating means for classifying into groups, and display means for displaying the strip group having a plurality of hierarchies which is calculated by said calculating means as a region to be displayed respectively in different states, the calculating means, said amplitude probability Cumulative and average distributions
A spectrum analyzer having an APD display function characterized by including means . 2. A signal under measurement is received according to desired sweep information.
Signal receiving processing means for receiving, and the signal under measurement received by the signal receiving processing means.
By sampling the signal based on multiple thresholds,
A plurality of outputs corresponding to sample values of the envelope of the signal under measurement
Sampling means for outputting a code, and the plurality of output codes output by the sampling means.
Histogram measurement to measure the histogram group corresponding to
A constant section, the hiss measured by the histogram measuring means
Based on the togram group and the desired sweep information.
The amplitude probability distribution (APD) of the constant signal is calculated, and
It is divided into band groups with multiple layers corresponding to the histogram groups.
Comparable computing means and the plurality of layers computed by the computing means
As a region to display each band group in different states
Display means for displaying, and the computing means calculates a function scale for the amplitude probability distribution.
In addition, the display means includes means for calculating the function scale coordinates, and each of the display means has a band group having the plurality of layers.
It is common to display as an area that should be displayed in different states.
, The function scale for the band group having the plurality of layers is shown in
A spectrum analyzer having an APD display function, characterized by including the means shown . 3. A signal under measurement is received according to desired sweep information.
Signal receiving processing means for receiving, and the signal under measurement received by the signal receiving processing means.
By sampling the signal based on multiple thresholds,
A plurality of outputs corresponding to sample values of the envelope of the signal under measurement
Sampling means for outputting a code, and the plurality of output codes output by the sampling means.
Histogram measurement to measure the histogram group corresponding to
A constant section, the hiss measured by the histogram measuring means
Based on the togram group and the desired sweep information.
The amplitude probability distribution (APD) of the constant signal is calculated, and
It is divided into band groups with multiple layers corresponding to the histogram groups.
Comparable computing means and the plurality of layers computed by the computing means
As a region to display each band group in different states
Display means for displaying, wherein the calculating means is for a desired value of the amplitude probability distribution.
Means for calculating to emphasize the contour lines of each of the bands, the display means for displaying each of the band groups having the plurality of layers.
It is common to display as an area that should be displayed in different states.
, The contour for the desired value in the amplitude probability distribution
A spectrum analyzer having an APD display function, comprising means for highlighting a line . 4. The display means has the plurality of layers.
Including means for displaying different color bands
The APD according to any one of claims 1 to 3, characterized in that
Spectrum analyzer with display function. 5. The histogram measuring means is the sample
Add the plurality of output codes output by the converting means.
Memory, histogram measurement status, measurement result
A switch for switching the output state and the histogram measurement status
And an adder for adding +1 to the output of the memory,
The register that returns the output of the calculator to the memory and the measurement result
Histogram measurement result of the memory output in the result output state
Interface circuit that outputs as
The APD according to any one of claims 1 to 4, characterized in that
Spectrum analyzer with display function. 6. A signal under measurement is received according to desired sweep information.
Transmitting the received signal under test based on a plurality of thresholds.
By sampling, the envelope of the measured signal
Output multiple output codes corresponding to sample values
And measure the histogram groups corresponding to the multiple output codes
Based on the histogram group and the desired sweep information
The amplitude probability distribution (APD) of the signal under measurement is calculated,
And has a plurality of layers corresponding to the histogram group.
And a step of classifying the belt groups having a plurality of layers in different states.
Displaying as a region to be shown, wherein the plurality of threshold values in the sampling are calibrated in advance.
Spectra characterized by further comprising steps
APD display method using a mobile analyzer. 7. A signal under measurement is received according to desired sweep information.
Transmitting the received signal under test based on a plurality of thresholds.
By sampling, the envelope of the measured signal
Output multiple output codes corresponding to sample values
And measure the histogram groups corresponding to the multiple output codes
Based on the histogram group and the desired sweep information
The amplitude probability distribution (APD) of the signal under measurement is calculated,
And has a plurality of layers corresponding to the histogram group.
And a step of classifying the belt groups having a plurality of layers in different states.
Displaying as a region to be shown, further comprising the step of accumulating and averaging the amplitude probability distributions.
A method for displaying an APD by a spectrum analyzer, which comprises: 8. A signal under measurement is received according to desired sweep information.
Transmitting the received signal under test based on a plurality of thresholds.
By sampling, the envelope of the measured signal
Output multiple output codes corresponding to sample values
And measure the histogram groups corresponding to the multiple output codes
Based on the histogram group and the desired sweep information
The amplitude probability distribution (APD) of the signal under measurement is calculated,
And has a plurality of layers corresponding to the histogram group.
And a step of classifying the belt groups having a plurality of layers in different states.
Displaying as an area to be shown, and performing a function rule calculation on the amplitude probability distribution, and
The method further comprises a step of calculating function scale coordinates, wherein the displaying step includes a band group having the plurality of layers.
Are displayed as areas that should be displayed in different states.
And a function for the band group having the plurality of hierarchies.
An APD display method using a spectrum analyzer, which is characterized by displaying a scale . 9. For a desired value of the amplitude probability distribution
Further comprising a step of calculating to enhance the contour lines
The displaying step includes a band group having the plurality of layers.
Are displayed as areas that should be displayed in different states.
And the contour for the desired value of the amplitude probability distribution.
Claims including the step of highlighting lines
AP by spectrum analyzer according to items 6 to 8
D display method. 10. The displaying step comprises the steps of:
Displaying a group of bands with different color bands
An APD display method using a spectrum analyzer according to any one of claims 6 to 9 . 11. Desirability of a measured signal over a plurality of frequencies
Signal reception processing means for receiving according to the sweep information, and the signal under measurement received by the signal reception processing means.
By sampling the signal based on multiple thresholds ,
A plurality of outputs corresponding to sample values of the envelope of the signal under measurement
A sample that outputs a code for each frequency of the plurality of frequencies
Output means for each frequency by the sampling means, and
The histograms corresponding to multiple output codes are
Histogram measuring means for measuring each wave number, and for each frequency by the histogram measuring means.
A plurality of defined histograms and the desired sweep information
Based on the amplitude probability distribution (APD) of the signal under measurement based on
Note: Calculated for each frequency
Means for classifying into a band group having a plurality of hierarchies corresponding to
And the plurality of layers calculated by the calculation means
As a region to display each band group in different states
And a display unit for displaying the AP.
Spectrum analyzer with D display function. 12. The calculation means calculates the amplitude probability distribution.
For that, calculate the function scale and the coordinate of the function scale.
Means for displaying the band groups having the plurality of layers.
It is common to display as an area that should be displayed in different states.
, The function scale for the band group having the plurality of layers is shown in
Having an APD display function characterized by including means for indicating
The spectrum analyzer according to claim 11. 13. The display means has the plurality of layers.
It includes a means for displaying each color band in a different color band.
The APD table according to claim 11 or 12, characterized in that
Spectrum analyzer with display function. 14. The histogram measuring means comprises:
The plurality of output codes output by the embodying means are
Dress memory, histogram measurement status, measurement results
A switch for switching the result output state and the histogram measurement
An adder for adding +1 to the output of the memory in the state,
A register for returning the output of the adder to the memory, and the measurement
In the result output state, the output of the memory is measured by the histogram.
It consists of an interface circuit that outputs the result.
The method according to any one of claims 11 to 13, characterized in that
Spectrum analyzer with APD display function. 15. Desirability of a measured signal over a plurality of frequencies
Receiving the received signal under test according to a plurality of thresholds.
By sampling, the envelope of the measured signal
A plurality of output codes corresponding to sampled values
And outputting histograms corresponding to the plurality of output codes for each frequency.
And measuring for each frequency, the plurality of histograms measured for each of the respective frequency
Amplitude probability of the measured signal based on the desired sweep information
The distribution (APD) is calculated for each frequency, and
Bands with multiple layers corresponding to multiple histograms
And a group of bands having a plurality of layers in different states.
And a step of displaying as an area to be shown.
APD table by spectrum analyzer characterized by
How to show. 16. The plurality of thresholds in the sampling.
The method further comprises the step of calibrating the value in advance.
According to the spectrum analyzer of claim 15,
APD display method. 17. A function rule calculation for the amplitude probability distribution.
As well as the step of calculating the function scale coordinates.
And a step of displaying the band group having the plurality of layers.
Are displayed as areas that should be displayed in different states.
And a function for the band group having the plurality of hierarchies.
The scale is displayed, according to claim 15 or 16.
APD display method by the described spectrum analyzer. 18. The step of displaying comprises:
Displaying a group of bands with different color bands
The screen according to any one of claims 15 to 17, characterized in that
APD display method by Pectrum Analyzer.