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JJG 954-2019: Digital Electroencephalographs
Status: Valid JJG 954: Evolution and historical versions
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| JJG 954-2019 | English | 489 |
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Digital Electroencephalographs
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JJG 954-2019
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| JJG 954-2000 | English | 599 |
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Verification Regulation of Digital electroencephalogram mapping and brain electric activity mapping
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JJG 954-2000
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PDF similar to JJG 954-2019
Basic data | Standard ID | JJG 954-2019 (JJG954-2019) | | Description (Translated English) | Digital Electroencephalographs | | Sector / Industry | Metrology & Measurement Industry Standard | | Classification of Chinese Standard | A56 | | Classification of International Standard | 17.220 | | Word Count Estimation | 21,293 | | Date of Issue | 2019 | | Date of Implementation | 2020-03-27 | | Issuing agency(ies) | State Administration for Market Regulation | JJG 954-2019: Digital Electroencephalographs---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
(Verification regulations of digital electroencephalograph)
National Metrological Verification Regulations of the People's Republic of China
Digital electroencephalograph
2019-09-27 released
2020-03-27 Implementation
Issued by the State Administration for Market Regulation
Verification Regulations of Digital EEG System
1 Scope
This regulation is applicable to the first verification, subsequent verification and use of digital EEG devices newly manufactured, in use and after repair.
In-use inspection, the digital EEG measurement module in other EEG measurement equipment can be implemented by reference.
This regulation does not apply to telemetry EEG, ambulatory EEG recorders, brain function monitors and special-purpose EEG
measuring equipment.
2 Reference documents
This regulation refers to the following documents.
JJG 1043-2008 EEG machine
OIMLR89.1990 Method and equipment used to verify the measurement performance of electroencephalograph
For dated reference documents, only the dated version applies to this regulation; for undated references
The latest version (including all amendments) is applicable to this regulation.
3 overview
The digital electroencephalogram (hereinafter referred to as the tested instrument) is a biological analog electrical signal generated by the activity of human brain tissue.
Input circuits, amplifiers, data acquisition and analog-to-digital converters are converted into digital quantities, and stored, replayed, displayed or printed.
Print out the time-domain EEG.
4 Measurement performance requirements
4.1 Voltage measurement
The maximum allowable error is calculated as ±10× (1 U1Uin)% (where U1 is the minimum value of the voltage measurement range, which is
It is 5 times the voltage value in the highest sensitivity. For example. when the highest sensitivity of the tested instrument is 1μV/mm, voltage measurement
The minimum value of the range is 5μV).
4.2 Time interval
The maximum allowable error is calculated as ±5× (1 TlTin)% (where Tl is the minimum value of the time interval measurement range, the
The value is 0.05s).
4.3 Amplitude-frequency characteristics
(1~60)Hz, the maximum allowable deviation is 5%~-10%.
4.4 Performance of low-pass filter (high-cut filter)
Should meet the requirements of A0.9Fc≥0.7A10≥A1.1Fc.
4.5 High-pass filter (low-cut filter) performance
Should meet the requirements of A0.9Fc≤0.7A10≤A1.1Fc.
4.6 Noise level
Not more than 3μV (peak-to-peak value).
4.7 Common mode rejection ratio
Each channel is not less than 1×104 (80dB).
4.8 Withstand polarization voltage
Add ±300mV DC polarization voltage, the maximum allowable deviation of the amplitude is ±5%.
5 General technical requirements
The inspected instrument should be marked with the manufacturer's name, model, factory number, and factory date, and the accessories should be complete. No shadow
Mechanical damage to normal operation. The keyboard and mouse are in good contact, and can smoothly and continuously select points to measure on the displayed waveform.
6 Measuring instrument control
6.1 Verification conditions
6.1.1 Environmental conditions
a) Ambient temperature. (20±10)℃;
b) Relative humidity. less than 80%;
c) Power supply. (220±11)V, (50±1)Hz;
d) The surrounding environment has no electromagnetic field interference that affects the normal operation of the digital EEG;
e) There should be a good grounding device.
6.1.2 Measurement standards and supporting equipment
See Table 1 for measurement standards and supporting equipment.
6.3 Verification method
6.3.1 Appearance and normality inspection
The appearance and normality inspection shall meet the requirements of Chapter 5.
6.3.2 Preparation and precautions before verification
6.3.2.1 In the verification, the instrument to be tested and the verification instrument must be well grounded.
6.3.2.2 The inspected instrument shall be warmed up according to the time specified in the instruction manual.
6.3.2.3 In order to obtain high measurement resolution, in the verification items that do not strictly specify the standard signal amplitude,
In the displayed graph, under the condition that the waveforms of adjacent channels do not affect the normal reading due to overlap, select the sensitivity of the tested instrument reasonably.
The amplitude of the standard signal of the verifier and the calibration instrument can make the displayed waveform amplitude as large as possible after recording, thereby reducing the measurement uncertainty.
6.3.3 Voltage measurement
6.3.3.1 The verification system is connected as shown in Figure 1.
6.3.3.2 Based on the bandwidth required to pass the EEG signal, reasonably select the time constant and
The setting value of the low-pass filter (for example, the time constant is set to 1s, and the cut-off frequency of the low-pass filter is set to 70Hz).
6.3.3.3 A square wave with a period of 0.1s is output from the verifier to the tested instrument. Select a verification point in Table 3 and follow Table 3
Set the sensitivity Sn of the tested instrument and the output voltage of the tester. The recording speed can be adjusted appropriately to make the signal of each channel clear.
Record and store the standard signal of each channel on the tested instrument and replay it.
Number of cycles. Record and store standard signals on the tested instrument, and replay and display them.
6.3.4.4 Among the signals of each channel displayed in the playback, find the one with the largest time interval deviation to measure, and measure 2
The time interval between periodic continuous waveforms. Calculate the relative error δTm of the time interval according to formula (2), which should meet the requirements of 4.2.
6.3.5 Amplitude-frequency characteristics
6.3.5.1 The verification system is connected according to Figure 1.
6.3.5.2 The time constant of the tested instrument is set to the maximum, and the low-pass filter and high-pass filter are set to "off" (if there is no
"Off" block select the highest frequency block).
6.3.5.3 Input the frequency of 10Hz and appropriate amplitude from the calibrator to the tested instrument (e.g. 100μV peak-to-peak value)
Standard sine wave signal, record its amplitude A10.
6.3.5.4 Under the condition that the output voltage amplitude of the verifier remains unchanged, press 1Hz, 5Hz, 20Hz, 30Hz,
60Hz changes its frequency in turn, and records, stores, and replays the recorded signal on the tested instrument.
6.3.5.5 Find the channel with the worst amplitude-frequency characteristic in the waveform displayed in the playback, and measure the sine wave waveform of each frequency in this channel
Amplitude. Take the 10Hz signal amplitude A10 as the reference value, and take the most deviation from A10 in the measured amplitude of the sine wave at each frequency.
The larger one is Ai. Use equation (3) to calculate the amplitude deviation Af of each frequency point, which should meet the requirements of 4.3.
6.3.6 Performance of low-pass filter
6.3.6.1 The verification system is connected according to Figure 1.
6.3.6.2 The time constant of the tested instrument is set according to 6.3.3.2, and the filter is set to the "off" gear (if there is no "off" gear, select the highest frequency gear).
6.3.6.3 The input frequency of the verifier to the tested instrument is 10Hz and the amplitude is appropriate (e.g., peak-to-peak value is 100μV)
Standard sine wave signal, record and store each waveform A10 on the tested instrument.
6.3.6.4 Select the low-pass filter with the tested frequency of Fc on the tested instrument, and change the output signal frequency of the tester respectively.
The rate is 0.9Fc, 1.1Fc (amplitude unchanged), and each waveform is recorded and stored on the tested instrument.
6.3.6.5 Play back the above stored waveforms, find the channel with the worst filtering characteristics, and measure the frequency in the waveform as
The signal amplitudes of 0.9Fc and 1.1Fc are A0.9Fc and A1.1Fc. The filter characteristics should meet the requirements of 4.4.
6.3.6.6 Repeat the steps 6.3.6.4 and 6.3.6.5 to verify the filters of each gear, and they should meet the requirements of 4.4.
6.3.7 Performance of high-pass filter
6.3.7.1 The verification system is connected according to Figure 1.
6.3.7.2 The time constant of the tested instrument is set according to 6.3.3.2, and the filter is set to the "off" gear (if there is no "off" gear, select the highest frequency gear).
6.3.7.3 The input frequency of the verifier to the tested instrument is 10Hz and the amplitude is appropriate (e.g., peak-to-peak value is 100μV)
Standard sine wave signal, record and store each waveform A10 on the tested instrument.
6.3.7.4 Select the high-pass filter with the tested frequency of Fc on the tested instrument, and change the output signal frequency of the tester respectively.
The rate is 0.9Fc, 1.1Fc (amplitude unchanged), and each waveform is recorded and stored on the tested instrument.
6.3.7.5 Play back the above stored waveforms, find the channel with the worst filtering characteristics, and measure the frequency in the waveform as
The signal amplitudes of 0.9Fc and 1.1Fc are A0.9Fc and A1.1Fc. The filter characteristics should meet the requirements of 4.5.
6.3.7.6 Repeat the steps of 6.3.7.4 and 6.3.7.5 to verify the filters of each gear, and they should all meet the requirements of 4.5.
6.3.8 Noise level
6.3.8.1 The verification system is connected as shown in Figure 2.
6.3.8.2 The time constant and low-pass filter of the tested instrument are set according to 6.3.3.2, and the sensitivity is set to the highest.
6.3.8.3 Set the electrode selector of the tested instrument to short-circuit the input terminals of each channel of the tested instrument to ground.
6.3.8.4 Set the tester to the noise test function, display, record and store the waveform on the tester for more than 10s.
6.3.8.5 Play back the stored waveform on the tested instrument. As shown in Figure 3, find the largest noise signal in each channel
The channel, and measure its amplitude UN, should meet the requirements of 4.6.
6.3.9 Common mode rejection ratio
6.3.9.1 The verification system is connected as shown in Figure 2.
6.3.9.2 The time constant and low-pass filter of the tested instrument are set according to 6.3.3.2, and the sensitivity is set to an appropriate position (e.g..
The sensitivity is set to 100μV/mm).
6.3.9.3 The common mode rejection ratio is set on the verifier, and the input frequency to the tested instrument is 50Hz and the amplitude is Ud (e.g.
100μV) differential mode signal; convert the tester to a common mode state, and input a voltage amplified by K times the common mode to the tested instrument
Modular signal. Record, store, and replay differential mode and common mode signals separately.
6.3.9.4 From the replayed signals, select the channel with the largest common mode signal amplitude, and measure the differential mode signal of this channel respectively
The amplitude U0, the common mode signal amplitude Uc. Calculate the common-mode rejection ratio CMRR (in dB) according to formula (4), which should conform to
4.7 requirements.
6.3.9.5 The common mode rejection ratio verification should be carried out in a laboratory with good grounding and anti-interference.
You can directly short-circuit the input terminal of the tested instrument and then add a common mode signal, and perform the verification according to the above method.
6.3.10 Withstand polarization voltage
6.3.10.1 The verification system is connected as shown in Figure 2.
6.3.10.2 The time constant and low-pass filter of the tested instrument are set according to 6.3.3.2, and the sensitivity is set to an appropriate position (such as.
The sensitivity is set to 100μV/mm).
6.3.10.3 A standard square wave signal with a peak-to-peak amplitude of 100μV and a period of 1s is output from the verifier to the tested instrument.
number. Record and store the unpolarized voltage and add 300mV and -300mV polarized voltage on the tested instrument.
The waveform at the time of compression, and playback of the stored signal.
6.3.10.4 Select the waveform with the largest change in the playback waveform, and measure the waveform amplitude value of the waveform without polarization voltage
U0, and the waveform amplitude values U and U- after adding 300mV and -300mV polarization voltage, take the deviation
The largest U0 is UE. Calculate the relative deviation δE of the polarization resistance voltage according to formula (5), which should meet the requirements of 4.8.
6.4
For instruments that are qualified according to the requirements of this regulation, a verification certificate will be issued; for instruments that are unqualified, a verification result will be issued
Notice, and indicate the unqualified items.
6.5 Verification cycle
The verification period of the tested instrument generally does not exceed 1 year.
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