JPH06261118A - Noise audible immunity evaluation tester - Google Patents

Abstract

PURPOSE:To provide a noise audible immunity evaluation tester which evaluates the noise audible immunity characteristic by measuring the noise signal produced between the telephone receiver by an acoustic coupling method. CONSTITUTION:A test signal generator 13 applies the test signals to the tested devices 1A and 1B via a programmable attenuator 14 in a common mode. The audible signal detector means 4A and 4B detect the audible noise signals produced between the telephone receiver terminals of both devices 1A and 1B. An applied signal measuring circuit 6 measures the level of the applied signal when the levels of signals detected by the means 4A and 4B exceed the limit level set previously in response to the noise audible sound pressure of the telephone receiver. Then an arithmetic storage circuit 11 outputs a radio of levels between the applied signal and the audible noise signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies a common mode test signal containing a high frequency component to a line such as a communication line or a power line connected to a device under test such as a telephone and whether or not it is heard as noise from a handset. The present invention relates to a noise audible immunity evaluation tester that measures and evaluates a noise audible immunity characteristic, which is the proof stress limit.

[0002]

2. Description of the Related Art Noise may be generated from the handset of a telephone due to the influence of external electromagnetic interference. This is the occurrence of so-called hearing loss. As a main external electromagnetic interference wave that causes an audible disturbance, there is a waveform shown by V ₀ in FIGS. 7 (a) to 7 (d). In FIG. 7, (a) is a case of an amplitude modulation (AM modulation) sine wave, (b) is a case of a power supply synchronizing pulse wave, (c)
Shows the case of a damped oscillatory wave, and (d) shows the case of an intermittent sine wave.

When these extraneous electromagnetic interference waves are induced in the communication line of the telephone, common mode (longitudinal) current penetrates into the equipment of the telephone connected to the communication line. Then, noise is often generated from the handset due to unbalanced impedance of the equipment circuit or detection characteristics of the entire equipment circuit due to the use of a large number of semiconductor circuit elements. The handset-pin when this waveform is generated as V _R shown in FIG. 7 (a) ~ (d) , which is the noise sound pressure by driving the receiver diaphragm is generated.

Note that V ₀ is an AM as shown in FIG.
In the case of a modulated sine wave, V _R is, for example, as described in 1992 IEICE Spring Conference Proceedings SB-3-2, a V H waveform consisting of a carrier component in which the V ₀ waveform is directly reduced, and an AM. It is known that the modulated wave has a waveform superimposed with a voice modulated wave waveform such as a VL waveform detected in the entire telephone circuit.

FIG. 8 is a block diagram showing a conventional structure of a noise audible immunity test system for applying such an AM-modulated sine wave to a device under test to evaluate the presence or absence of noise audible from a receiver. is there. As shown in the figure, a device under test (EUT) 51 such as a telephone is supported by an insulating support base 52 at a constant height h from above the pseudo ground plane. EUT
The handset 51 of the handset 53 is fitted into the microphone 54 via the acoustic coupler 55. The noise from the earpiece converted into the electric signal by the microphone 54 is the level meter 5 that displays the electric signal output of the microphone 54.
Displayed at 6. That is, the audible noise sound pressure P from the handset
The level meter 56 can determine the size of the.

The handset 53 has a pseudo-hand circuit 57 equivalent to the ground impedance when a person holds the handset.
Are connected. Handset 53 and microphone 54
Is a sound insulation box 58 for preventing ambient noise other than audible noise from the handset from entering the microphone 54.
Is stored in.

A test signal applicator 60A for applying a test AM-modulated sine wave (test signal) to the EUT 51 in a common mode is connected to a communication line between the EUT 51 and an opposite communication device 61 such as a pseudo exchange. . Test signal applicator 60
A is a test signal generator (SG) 59 for generating a test signal.
And a common mode choke coil 62 for applying the applied test signal only to the EUT side, not to the opposite communication device 61 side. In addition, E
A line opening switch 63 is provided between the UT 51 and the test signal applying unit 60A.

In such a test system, when an AM-modulated sine wave such as V ₀ shown in FIG. 7A is applied to the communication line in the common mode as a test signal, the common mode current iv flows in the communication line. Invades EUT51. Then, the common mode current is converted and detected by the unbalanced impedance in the circuit of the EUT 51, the semiconductor circuit, etc., and causes audible noise in the receiver. Audible noise from the handset enters microphone 54 where it is converted to an electrical signal. Since the level meter 56 swings in accordance with the electric signal, the measurer can know the noise sound pressure P from the swing. In this way, the noise sound pressure from the handset is extracted by acoustic coupling.

The audible immunity of the EUT 51 is obtained as an open end common mode voltage when the line opening switch 63 is opened by applying an applied voltage when a sound pressure P (= P ₀ ) occurs at the limit at which noise starts to be heard. . Therefore, the noise audible immunity characteristic of the EUT 51 can be obtained by measuring the open end common mode voltage while changing the carrier frequency f of the test signal from the SG 59 and plotting the measured value.

FIG. 9 shows a case where one test signal applicator 60A is connected to a system including a plurality of EUTs. In a system such as a button telephone device or a business phone, slave devices S ₁ , S ₂ , ..., S _M are connected to a main device (M) 70 via an extension line such as a home bus line, and the main device 70 is used. Opposite telephone S _N 71 on the opposite communication line side
Are connected. The test signal from the test signal applicator 60A is then used to evaluate the audible immunity of such a system.

[0011]

When trying to evaluate the noise audible immunity characteristics of various telephones using the characteristic evaluation tester shown in FIG. 8, it is necessary to swing the level meter 56 appropriately corresponding to the noise sound pressure. become. However, the shape of the earpiece varies depending on the handset. When the earpieces having different shapes are attached to the acoustic coupler 55, the fitting condition between the receiver and the acoustic coupler 55 changes, and the acoustic coupler 55 may not be properly coupled to the microphone 54. In such a case, there is a problem that the vibration of the level meter 56 is unstable especially near the audible sound pressure limit, and it becomes difficult to detect an appropriate sound pressure level.

Further, the evaluation based on the noise sound pressure targets only the AM-modulated sine wave as shown in FIG. 7 (a). Figure 7
(B) ~ For the audible electromagnetic disturbance (d), the because correspondence between V _R wave and the noise sound pressure generated between handset terminals is not clear. Therefore, there is a problem in that the characteristics of the audible electromagnetic interference waves shown in FIGS. 7B to 7D cannot be evaluated.

[0013] With the configuration shown in FIG. 9 to evaluate the audible immunity of the entire system, the child telephone S ₁ is a receiver and the EUT of the main apparatus 70, S _2, · · ·, to S _M and the opposite telephone S _N Noise sound pressure (P
₁ , P ₂ , ..., P _N ) must be measured to know which one corresponds to the smallest audible immunity, etc. However, if the test system shown in FIG. 8 is used for such a plurality of EUTs, the acoustic coupler 55, the sound insulation box 58, etc. corresponding to each EUT are required. Therefore, there has been a problem that a large amount of equipment is required and it takes a lot of time to arrange test systems such as coupling.

The present invention provides a noise audible immunity evaluation tester for evaluating noise audible immunity characteristics by measuring a noise signal generated between receiver terminals, instead of the noise sound pressure measurement by the acoustic coupling method. The purpose is to

[0015]

A noise audible immunity evaluation tester according to a first aspect of the present invention applies a test signal to an EUT in a common mode, and raises, stops, and stops the output level of the test signal. An applied level setting means for resetting to zero, an audible signal detecting means for detecting a noise audible signal generated between the receiver terminals of the EUT having a high frequency common mode high impedance characteristic, and a level of the noise audible signal by the audible signal detecting means. However, there is provided an applied signal detecting means for measuring an applied signal level when a predetermined limit level corresponding to the noise audible sound pressure from the handset is exceeded.

A noise audible immunity evaluation tester according to a second aspect of the present invention applies a test signal to the EUT in a common mode, and an application level for increasing, stopping, and returning to zero the output level of the test signal. It has setting means and high frequency common mode high impedance characteristics,
An audible signal detecting means for detecting a noise audible signal generated between the receiver terminals of T, and an applied signal detecting means for measuring the level of the applied signal of the device under test by the applied level setting means,
The level of the noise audible signal detected by the audible signal detecting means and E
And a characteristic evaluation means for obtaining a ratio to the applied signal level of the UT.

A noise audible immunity evaluation tester according to a third aspect of the present invention is the tester according to the first or second aspect of the present invention, wherein the applied level setting means is used to receive an amplitude-modulated sine wave as a test signal. It is intended to be applied to the test equipment.

A noise audible immunity evaluation tester according to a fourth aspect of the present invention is the noise audible immunity evaluation tester according to the first or second aspect of the present invention, in which the applied level setting means is other than an amplitude-modulated sine wave as a test signal. A signal having a repetition frequency within the audible band is applied to the device under test, and the audible signal detecting means and the noise audible signal are
The input is detected as a spectrum or a waveform.

[0019]

The applied level setting means in the present invention is a mode in which a test signal containing a high frequency wave such as an AM-modulated sine wave is E
Apply to the UT line. The applied signal detection means measures the applied signal level when the level of the noise audible signal detected between the handset terminals exceeds the predetermined limit level of the noise audible signal corresponding to the noise audible sound pressure, Enables testing of high frequency unbalanced characteristics without using acoustic coupling.

The characteristic evaluation means obtains the noise audible immunity characteristic by the ratio of the level of the noise audible signal detected between the receiver terminals and the level of the applied signal of the EUT.

[0021]

1 is a block diagram showing the configuration of a noise audible immunity evaluation tester according to an embodiment of the present invention. Here, the case where the noise audible immunity characteristics of two EUTs (EUTA, EUTB) 1A and 1B each having the handset 3A (or the handset 3B) are measured is shown. As shown in the figure, EUTA and EUTB are installed via a pseudo exchange 61.

A test signal applicator 60 is inserted between EUTA and EUTB. Between the receiver terminals R1 and R2 of both EUTs, an audible signal detecting means (hereinafter referred to as an audible signal detecting means) 4 between the receiver terminals such as a differential probe.
A and 4B contact each other. The audible signal detecting means 4A and 4B are
The audible noise signals V _Ra and V _Rb generated between the terminals are detected. The audible signal detecting means 4A and 4B are connected to the receiver terminal R.
A high impedance is provided between each contact terminal and the frame ground so that a high-frequency common mode signal generated at these terminals does not flow to the frame ground side even if the terminals 1 and R2 are contacted.

The applied signal detector 5 is composed of a high impedance probe or the like, and introduces the voltage at the open end after the line open switch 63 is opened. The applied signal measuring circuit 6 is
The level of the introduced voltage, that is, the open end common mode voltage level V ₀ is measured.

The BPF section 7 consisting of a band pass filter (BPF) corresponding to each audible signal detecting means passes only the audible signal in the voice band among the signals detected by the audible signal detecting means 4A and 4B. Each BPF is switched and selected by the channel selection switch 8. The channel selection switch 8 has a switching number n. Therefore, it is possible to measure n EUTs.

The audible band signal measuring circuit 9 introduces the output of the channel selection switch 8 and measures the level of the audible signal in the voice band. The audible signal comparison circuit 10 also compares the level of the output of the channel selection switch 8 with a predetermined level. The arithmetic storage circuit 11 inputs the output of the applied signal measuring circuit 6 and the output of the audible band signal measuring circuit 9, performs arithmetic operations on them, and stores the arithmetic result. Also,
The necessary information is displayed on the display unit 12.

The test signal generator 13 has a carrier frequency setting circuit 131 for setting a carrier frequency and an AM modulation circuit 132 for amplitude-modulating a carrier wave, and generates a test signal. In addition, the programmable attenuator 14 includes an attenuator (ATT) 141 that attenuates a test signal, and an ATT 14
An applied level setting circuit 142 for instructing the attenuation amount to 1;
It has a level holding circuit 143 for giving a level holding instruction to the applied level setting circuit 142 and a zero restoration circuit 144 for making the output of the ATT 141 zero, and controls the level of the test signal. The output of the programmable attenuator 14, that is, the output of the ATT 141 is amplified by the amplifier 16 and then supplied to the test signal applicator 60.

The channel selection switch 8 and the line opening switch 63 are switched by the switch switching section 15. That is, in the switch switching section 15, the channel selection switch 8 and the line opening switch 63 are operated by driving the magnets M1 and M2. In addition, the audible signal comparison circuit 10 includes an LE for display.
D17 is provided. Manual setting units 18, 19, and 20 are connected to the test signal generator 13, the programmable attenuator 14, and the switch switching unit 15, respectively.

Therefore, in this embodiment, the applied level setting means is composed of the test signal generator 13 and the programmable attenuator 14. The audible signal detecting means is composed of the audible signal detecting means 4A and 4B. The applied signal detecting means is composed of an applied signal detecting section 5 and an applied signal measuring circuit 6. Further, the characteristic evaluation means is the arithmetic storage circuit 1
It is composed of 1.

Hereinafter, in the configuration shown in FIG. 1, FIG.
When applying an AM-modulated sine wave as shown in
The operation for obtaining the noise audible immunity characteristics of A and EUTB will be described.

First, the measurer operates the manual setting section 20 to give an instruction to the switch switching section 15 to bring the line opening switch 63 into a short-circuited state, and at the same time, a BPF corresponding to any of the EUTs (for example, The BPF of CH1) is instructed to connect the channel selection switch 8. In addition, the manual setting unit 19 is operated to set the applied frequency band and the frequency step-up width. The carrier frequency setting circuit 131 generates a carrier wave of the first frequency (for example, the minimum frequency) in the set applied frequency band. The AM modulation circuit 132 uses the carrier wave as a voice band signal having a predetermined frequency (for example, f = 1 kHz).
Signal) whose amplitude is modulated.

Further, the measurer operates the manual setting section 20 to set the step-up width of the applied signal level.
Alternatively, the level is set to be continuously variable. In the programmable attenuator 14, the applied level setting circuit 14
2 is ATT with set step width or continuously variable
The ATT 141 is controlled so that the output of 141 is changed. Therefore, the programmable attenuator 14 outputs an AM modulated wave whose level changes sequentially, and the AM modulated wave is given to the test signal applier 60 through the amplifier 16.
The test signal applicator 60 applies the AM modulated wave to EUTA as a test signal.

On the other hand, the audible signal detecting means 4A is
Audible noise signal V _Ra generated between the receiver terminals of the (Fig. 7 (a)
Including VH and VL shown in FIG. ) Is detected. Then, the detected audible noise signal is sent to the connected BPF.
The BPF only passes audio signals in the voice band. The audible signal in the voice band is transmitted through the channel selection switch 5 to the audible band signal measuring circuit 9 and the audible signal comparing circuit 1.
Input to 0.

The audible signal comparison circuit 10 compares the level of the inputted audible signal with a predetermined signal level V _R0 . The signal level V _R0 is the level VL (that is, VL ₀ ) of the voice band signal corresponding to the occurrence of the limit audible sound pressure P ₀ . The relationship between V _R0 and P ₀ is A
It is known that when the M-modulated wave is applied, it is almost determined according to the type of the handset (for example, piezoelectric type or electrostatic type). Then, the audible signal comparison circuit 10 turns on the LED 17 and instructs the level holding circuit 143 of the programmable attenuator 14 to fix the output level of the ATT 141 when the level of the audible signal exceeds V _R0. . At that time, the audible signal comparison circuit 10 causes the switch switching unit 15 to connect the line opening switch 6
Give an instruction to make 3 open. The switch switching unit 15 accordingly opens the line opening switch 63.

The applied voltage detector 5 detects the voltage between the receiver terminals. Therefore, at this time, the open-end common mode voltage is input to the applied voltage detection unit 5. The applied signal measuring circuit 6 measures the open end common mode voltage level V ₀ and sends it to the arithmetic storage circuit 11. Arithmetic storage circuit 11
Stores the open end common mode voltage level V ₀ and plots it on the frequency axis of the display unit 12. The arithmetic storage circuit 11 may be configured to take the ratio of the open-ended common mode voltage level V ₀ and the level VL of the voice band signal output from the audible band signal measurement circuit 9 and plot it.

Next, the arithmetic storage circuit 11 drives the zero restoration circuit 144 of the programmable attenuator 14 to drive the ATT 14
The output level of 1 is set to zero. The zero recovery circuit 144 is A
After completing the control to set the output level of TT141 to zero,
The switch switching unit 15 is instructed to bring the line opening switch 63 into the short-circuited state. The switch switching unit 15
After the switch switching process is performed, the carrier frequency setting circuit 131 of the test signal generator 13 is notified of that fact. Then,
The carrier frequency setting circuit 131 generates a carrier wave of the next frequency in the set applied frequency band. Then, each circuit executes the above operation again.

Through the above processing, the open end common mode voltage level (applied voltage level) V ₀ is measured for all frequencies in the set applied frequency band, and the noise audible immunity characteristic is obtained. Next, the magnet M2 of the switch switching unit 15 is driven and the channel selection switch 8 is switched to the CH2 side. Then, the noise audible immunity characteristic of EUTB is obtained by the same processing as the above processing.

As described above, the threshold level V _RO (= V L ₀ ) in the audible signal comparison circuit 10, the step-up width or continuous variable width of the applied signal level by the programmable attenuator 14, and the test signal generator 13 If the step-up width or the continuous variable width of the frequency is set in advance and then the above-described processing is performed, the noise audible immunity characteristics of a plurality of EUTs are automatically obtained. In the above embodiment, the measurement is automatically performed when the step-up width of the applied signal level or the step-up width of the frequency is set first, but the applied signal level or frequency is set manually each time. It can also be configured to.

FIG. 2 shows the EU thus obtained.
It shows an example of noise audible immunity characteristics of TA and EUTB. The vertical axis represents the applied signal level V ₀ or the level of the voice band signal V ₀ when the level VL of the voice band signal of the audible noise signal V _Ra or V _Rb exceeds the threshold level V _R0 which is the audible limit value. Converted attenuation expressed as a ratio with VL (α _L = 20 log (V ₀ / V
L) and α _L ′ = 20 log (V ₀ / VL ^′ ), whichever is acceptable. In the figure, Vh or α _L0 is a noise audible immunity evaluation level value (a recommended value draft by a standardization organization such as IEC).

In the case of this example, the evaluation level value Vh (or the conversion attenuation evaluation value α for noise audible immunity evaluation)
The frequency ranges of EUTA and EUTB satisfying _L0 , α _L0 ^' ) are f1 or less and f2 or less, respectively, and for the same applied signal level V ₀ , the EUTB is more than the EUT.
It can be easily determined that the immunity level of A is small.

That is, the noise audible immunity of the EUT can be evaluated easily and in a short time from the obtained noise audible immunity characteristics and the evaluation level value Vh. Further, according to the present invention as described above, since the configuration is such that the electric signal between the receiver terminals is extracted and evaluated without using the conventional acoustic coupling method, an acoustic coupler, a sound insulation box, etc. are not required. Therefore, particularly when many EUTs are connected to the home bus line as in the configuration shown in FIG. 9, noise audible immunity evaluation and the like can be easily performed. Further, noise audible immunity evaluation on the main unit or the opposite communication device side due to an increase in the imbalance of the extension system circuit that occurs when the number of connected EUTs is sequentially increased can be easily performed.

In the above embodiment, the channel selection switch 8 is used to measure V _Ra and V _Rb for two EUTs.
Although the output of each BPF is input to the audio signal comparison circuit 10, the audio signal comparison circuit 1
The configuration may be such that 0 selects one input.

Further, in the explanation of the operation of the above embodiment, FIG.
Although the case of using the AM-modulated sine wave as shown in (a) has been described, the waveforms shown in FIGS. 7B to 7D can also be evaluated. When evaluating such a waveform, for example, the audible noise signals V _Ra and V _Rb generated between the terminals and the applied voltage are captured as either a spectrum or a waveform. In the case of capturing with a spectrum, the audible band signal measuring circuit 9 and the applied voltage detecting circuit 6 are composed of a spectrum analyzer. When capturing them with waveforms, configure them with a waveform analyzer such as a memory scope. Further, the threshold level V _RO in the audible signal comparison circuit 10 is a spectrum level or a waveform level corresponding to the limit audible sound pressure. In this way, the noise audible immunity evaluation can be performed on the waveforms shown in FIGS. Therefore, it is possible to perform noise audible immunity evaluation on a continuous pulse waveform and the like, which cannot be performed by the conventional acoustic coupling method.

FIG. 3 is a configuration diagram showing the configuration of a test system in which EUTA is terminated by the equivalent impedance of the handset circuit. The equivalent impedance is EUTA in FIG.
It corresponds to the handset load system of. In FIG. 3A, Z _T is the equivalent impedance of the transmitter seen from the transmitter terminals T1 and T2 of the EUT, Z _R is the equivalent impedance of the receiver seen from the receiver terminals R1 and R2, and Zhg is the transmitter / receiver terminal T.
It is the equivalent impedance between 1, T2, R1, R2, and the pseudo ground. FIG. 3B shows a configuration in which the EUT is terminated by these equivalent impedances instead of the handset in the arrangement of the handset load system. This can simplify the arrangement of the EUT.

FIG. 4 is a configuration diagram showing a configuration example of the audible signal detecting means 4A, 4B by the differential probe. In the figure, 21 is a contactor that contacts the receiver terminals R1 and R2 to capture the signal level between the receiver terminals, and 22 is a common mode in which the common mode attenuation is large over a wide band and the differential mode attenuation is small or constant. A choke coil, 23 is an attenuating element, 26 is a metal differential probe body including a differential signal detecting element 24 such as FET and an amplifier 25, and 27 is a differential probe body 26.
Is an outer conductor of the connected coaxial cable.

The contactor 21 detects a signal between the receiver terminals by touching the receiver terminals R1 and R2 of the EUT to which a test signal having a high frequency component such as a common mode AM-modulated sine wave or a continuous pulse waveform is applied. To do. In that case,
If the common mode choke 22 and the attenuation element 23 are not provided, the high frequency component of the common mode signal generated at the receiver terminals R1 and R2 is the stray capacitance Cg between the differential signal detection element 24 and the differential probe body 26. Through the outer conductor 27 of the coaxial cable. Therefore, the signal between the terminals of the handset fluctuates greatly before and after the contact with the differential probe. However, if the common mode choke 22 and the attenuation element 23 are inserted, the high frequency component of the common mode signal is blocked by these. Therefore, according to the configuration shown in FIG. 4, even if the differential probe is brought into contact with the receiver terminals R1 and R2, the signal between the receiver terminals does not change and proper measurement can be performed.

FIG. 5 is a structural diagram showing another structural example of the audible signal detecting means 4A, 4B. As shown in the figure, the photoelectric conversion probe 34, which is an audible signal detecting means, is connected to the optical modulator 3
1, a light source 32 such as a laser, and an OE converter 33 for converting an optical signal into an electric signal.

The photoelectric conversion probe 34 uses two antenna elements of a dipole antenna disclosed in, for example, Japanese Patent Laid-Open No. 2-275370 as contacts. When detecting the inter-terminal signal from the EUT, the intensity of the optical signal from the light source 31 is modulated by the inter-terminal signal in the optical modulator 31. Then, the O-E converter 33 returns the optical signal to an electric signal. In such a probe, only the contact portion is made of metal, and the detected inter-terminal signal is converted into light by the optical modulator 31, so that the receiver terminal R
Even if a common-mode high-frequency signal exists at 1 and R2, there is no fluctuation in the signal between terminals due to probe contact.

FIG. 6 is a block diagram showing the configuration of a noise audible immunity evaluation tester according to another embodiment of the present invention. FIG. 6 shows a more automated process using a personal computer or the like. That is, in place of the arithmetic storage circuit 11, a measurement control unit 40 and a storage unit 41 such as a personal computer are provided.
Further, a setting unit 42 connected to the measurement control unit 40 is provided instead of the manual setting units 18, 19, 20.

The applied signal measuring circuit 6, the audible band signal measuring circuit 9, the audible signal comparing circuit 10, the test signal generator 1
3, the programmable attenuator 14, and the switch switching unit 15 are connected to the measurement control unit 40 by the GPIB bus.

With such a configuration, the noise audible immunity characteristic can be obtained by the same processing as the processing for obtaining the noise audible immunity characteristic by the configuration of the above embodiment. That is, according to the setting of the setting unit 42, the measurement control unit 40 sets the applied voltage level, frequency, etc. for the switch switching unit 15, the programmable attenuator 14, and the test signal generator 13. Then, the measurement control unit 40
The outputs of the applied signal measurement circuit 6, the audible band signal measurement circuit 9, and the audible signal comparison circuit 10 are input, and the same processing as that of the arithmetic storage circuit 11 in FIG. 1 is performed.

[0051]

As described above, according to the present invention, the noise audible immunity evaluation tester produces the noise sound pressure by the audible signal detecting means which is less affected even when the noise audible immunity evaluation tester contacts the receiver terminal. Since it is a configuration that electrically measures the inter-signal, it solves the problems such as the difficulty of mounting the handset at the time of acoustic coupling due to the shape of the earpiece and the instability of the detection level due to improper mounting, Many EUTs
When simultaneously measuring the audible immunity of the above, there is an effect that it is possible to provide the one capable of performing the measurement with good reproducibility in a short time.

If the audible signal detecting means and the applied signal detecting means detect the input as a spectrum or a waveform, an audible immunity to a test signal for an external electromagnetic interference wave other than the AM-modulated sine wave is obtained. There is an advantage that the characteristics can be evaluated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a noise audible immunity evaluation tester according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an example of a noise audible immunity characteristic.

FIG. 3 is a configuration diagram showing a configuration of a test system in which an EUT is terminated with an equivalent impedance of a handset circuit.

FIG. 4 is a configuration diagram showing a configuration example of an audible signal detection means.

FIG. 5 is a configuration diagram showing another configuration example of the audible signal detection means.

FIG. 6 is a block diagram showing the configuration of a noise audible immunity evaluation tester according to another embodiment of the present invention.

FIG. 7 is a waveform diagram showing an external electromagnetic interference wave and a noise waveform from a receiver.

FIG. 8 is a configuration diagram showing a configuration of a conventional noise audible immunity test system.

FIG. 9 is a configuration diagram showing a configuration in which one test signal applicator is connected to a system including a plurality of EUTs.

[Explanation of symbols]

 1A, 1B EUT 4A, 4B Audible signal detection means 5 Applied signal detection unit 6 Applied signal measuring circuit 7 BPF unit 8 Channel selection switch 9 Audible band signal measuring circuit 10 Audible signal comparison circuit 11 Arithmetic memory circuit 12 Display unit 13 Test signal generation Device 14 Programmable attenuator 15 Switch switching unit 16 Amplifier 40 Measurement controller 41 Storage unit 42 Setting unit

Claims (4)

[Claims] 1. A noise audible immunity evaluation tester for evaluating a noise audible immunity by applying a test signal including a high frequency component from a line of a device under test, and applying the test signal to the device under test in a common mode. Which has an applied level setting means for raising, stopping, and returning to zero the output level of the test signal, and has a high-frequency common mode high impedance characteristic, and detects a noise audible signal generated between the receiver terminals of the device under test. And an applied signal detection for measuring the applied signal level when the level of the noise audible signal by the audible signal detection means exceeds a predetermined limit level corresponding to the noise audible sound pressure from the receiver. A noise audible immunity evaluation tester comprising: 2. A noise audible immunity evaluation tester for evaluating a noise audible immunity by applying a test signal containing a high frequency component from a line of the device under test, and applying the test signal to the device under test in a common mode. Which has an applied level setting means for raising, stopping, and returning to zero the output level of the test signal, and has a high-frequency common mode high impedance characteristic, and detects a noise audible signal generated between the receiver terminals of the device under test. An audible signal detecting means, an applied signal detecting means for measuring the level of an applied signal of the device under test by the applying level setting means, and a noise audible signal level and an applied signal level detected by the audible signal detecting means. A noise audible immunity evaluation tester comprising a characteristic evaluation means for obtaining a ratio. 3. The applied level setting means applies an amplitude-modulated sine wave as a test signal to the device under test, and the audible signal detecting means detects a modulated wave generated between the receiver terminals of the device under test. The noise audible immunity evaluation tester according to claim 1 or 2. 4. The application level setting means applies a signal other than the amplitude-modulated sine wave as a test signal and having a repetition frequency within the audible band to the device under test, and the audible signal detecting means comprises: The noise audible immunity evaluation tester according to claim 1 or 2, wherein the noise audible signal is detected as a spectrum or a waveform, and the applied signal detecting means detects the applied signal as a spectrum or a waveform.