How to choose a signal level meter

[wxing]

TV signal level meter is to evaluate, test the quality of radio and television signals, commonly used in measuring instruments. This paper describes the common measurement of signal level meter.


1. Measurement indicators of field strength intensity



Main measurement indicators of field intensity are: frequency range, measurement range, measurement accuracy, sensitivity, resolution and so on.



TV Signal Level Meter’s frequency range is generally between 46 ~ 870MHz, covering VHF, FM, UHF television, including the addition of channels. Field intensity with Satellite TV signal measurements, is also covering 950 ~ 2150MHz satellite band.



In general, the field intensity level measurement error is±(1-3)dB. Field intensity that can achieve±1dB, its precision is considered to be very high. Because in the measurement procedure, the standing wave has a great impact on accuracy, and temperature and other external conditions also affect the accuracy of the measurement. Noise and other interference also have a great impact when measure small signals, so it is difficult to reach the accuracy less than 1dB.



Sensitivity is also an important indicator of field strength meter. In general, the TV with better function can received image more than in 60dBuV, and can receive television images in 50dBuV, it is difficult to receive if it is below 40dBuV, and in 30dBuV nothing can be seen. But the field intensity is different, it can generally measure 20-30dBuV weak TV signal, and display the image in 40dBuV, and be able to synchronize correctly. Therefore, the general range of field intensity level is around the 20-130dBuV



2. Digital TV measurement



The digital TV broadcast is becoming more and more popular, the cable TV of many countries have become digital, delivers to users more TV and radio programs at higher quality. Digital TV has its own standard. As for digital signal level meter, the functions and parameters are also varying from analog signal level meter, some more parameters needs to be tested.

First the signal level was replaced by digital average power, and MER (modulation error rate), BER (bit error rate) also need to be tested. Some meters can test constellations. If you want to see TV picture, the TV monitoring function is needed. As the population of digital broadcasting, almost signal level meters come with function of digital average power measurement.



3. How to choose a signal level meter?



Signal level meter have many functions that can make the test work easy, users can choose a model that really meets your requirements, and then select a cost-effective one. If you need it to calibrate your equipments, the accuracy should be within +/-1dB; if you need to view the spectrum, you can select one with spectrum analyst function. if you want it for test or maintenance work, compact and economic one is better.



If you also want to test digital satellite TV, you need a DVB-C and DVB-S, DVB-S2 combo meter, DVB-T meter is used to test digital terrestrial TV broadcasting.



Signal level meter can also be integrated to other equipments to fulfill automatic measurement and analyst, and then you will need more powerful signal level meter with RS232, GP-IB, or USB interface.



By Deviser technology

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