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Introduction to Click Testing

Release time:

2022-09-26 00:00

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　　1. Definition of clicking sound

　　The switching operation of thermostatically controlled appliances, automatically programmed machines and other electrically controlled or operated appliances can produce intermittent disturbances. The subjective impact of staccato disturbances varies with the repetition rate and amplitude present in the audiovisual. Therefore, different types of intermittent harassment should be distinguished. Intermittent disturbances are only measured with quasi-peak detector receivers mentioned in 5.1.1 and specified in Chapter 4 of CISPR16-1-1:2003. See the guidelines in Appendix C of the standard "GB 4343.1-2018 Electromagnetic Compatibility Requirements for Household Appliances, Electric Tools and Similar Appliances Part 1 Emission".

　　For intermittent disturbances, the click limit Lq is increased on the relevant continuous disturbance limit L:

　　44dB N <0.2, or

　　20lg(30/N )dB 0.2≤N <30

　　NOTE: Examples of intermittent disturbances classified as clicks are shown in Figures a, b, and c.

　　Clicking sound, also known as intermittent interference voltage, is a kind of voltage disturbance whose amplitude exceeds the quasi-peak limit of continuous disturbance, and whose duration is not more than 200ms, and the latter disturbance is at least 200ms away from the previous disturbance, and the duration is longer than the measurement receiver Signal determination of the IF reference level. The radiated pulses are so named because of their voltage characteristics that they cause the radio to produce the "click, click" sound.

　　Click (click), a voltage disturbance whose amplitude exceeds the quasi-peak limit of continuous disturbance and whose duration is not greater than 200ms, and the latter disturbance is at least 200ms away from the previous disturbance, and the duration exceeds the intermediate frequency reference level of the measuring receiver Signal OK. A click may contain many pulses, in which case the relevant time is the time from the beginning of the first pulse to the end of the last pulse.

　　The click test is an important test item in the EMC test of civil electronic products. Click rate N (click rate N): generally refers to the number of clicks or the number of switching operations within 1 minute. This number is used to determine the limit of clicks. Click limit Lq (Clcck limit Lq): The corresponding limit for continuous disturbances measured with quasi-peak detectors, plus a fixed value determined by the click rate N. The click limit applies to disturbances rated by the upper quartile.

　　2. Click test steps:

　　2.1 Determine the minimum observation time T

　　For appliances that do not stop automatically, T is the shorter of the following:

　　a) record 40 clicks or 40 switching operations;

　　b) 120 minutes.

　　For self-stopping appliances, T is the duration of the minimum number of complete programs required to produce 40 clicks or the associated 40 switching operations. 120 minutes after the start of the test, if 40 clicks have not been produced, the test is stopped after the running program ends.

　　2.2 Determining the click rate N

　　The click rate shall be determined under the specified operating conditions, or when not specified, under the most unfavorable conditions (maximum click rate) in the typical environment of use.

　　The general click rate is the number of clicks per minute determined by the formula N=n1/T, where n1 is the number of clicks within the observation time T.

　　For some specific appliances (such as refrigerators, freezers, electric irons, etc., see standard appendix A for details), the click rate N is determined by the formula N=n2*f/T, and n2 is the switch within the observation time T Operand, f is the factor of the appliance (see Standard Appendix A for details).

　　NOTE: When determining click rate, the 148.5 kHz-500 kHz band is based on the measured click rate at 150 kHz; similarly, the 500 kHz-30 MHz band is based on the measured click rate at 500 kHz. That is to say, of the data obtained through the four-channel test of the click analyzer, only the data of two frequency points are valid. For momentary switching, it is only necessary to determine the duration of the pulse at 500 kHz.

　　2.3 Determining the click limit Lq

　　The relevant click limit value Lq for intermittent disturbance is to add a fixed value to the relevant continuous disturbance limit value L:

　　2.4 Judgment method

　　a) If the click rate N of the appliance is determined from the number of clicks, if not more than a quarter of the number of clicks recorded during the minimum observation time T exceeds the click limit Lq, the click limit value Lq shall be The appliance under test is considered to comply with the limit values.

　　b) if the click rate N of the appliance is determined by the number of switching operations, if not more than a quarter of the number of clicks produced by the switching operations recorded during the minimum observation time T exceeds the click limit value Lq , the appliance under test shall be considered to comply with the limit requirements.

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