The new RED directive, effective June 13, 2017, includes three new standards for broadcast sound and video receiver equipment (EN 303 345, EN 303 340, EN 303 372-2). R&S company provide the BTC test system for turn-key solution. The system is very powerful, it includes signal generator and signal analyser functions. But as you know, The BTC test system is very expensive. After reviewing the test standard, we know the test standards need two signal generators, one for useful signal (FM, AM, DAB, DVB), one for inference signal (FM, AM, DAB, DVB, LTE) and one audio analyser. General all RF test labs have these kind instruments. Based on these instruments, we use software to control these instruments, it can finish all the tests easily by one key. It is the most low-cost and high efficiency method. Below is the BTS system for EN 303 345 test introduce.
Picture 2：BTS（303 345）test systme
The BTS test system need two signal generators and one audio analyser, It compatible main instrument manufacturer, like R&S, Keysight(Agilent) and so on. It can use the instruments which test lab already have to lower the cost.
The demo system use one signal generator model N5182A for interference signal source, one signal generator model E4421A for useful signal source. The audio analyser is model Agilent U8903A. As picture 2 show.
Open the software, The UI of software is very simple. As picture 3 show, It use for instruments connection. Picture 4 is for FM test, Picture 5 is for AM test.
As picture 3 show. Search equipment is use for finding the equipment, after search the equipment, then click connect the equipment.
As picture 4 and 5 show. The button Start is use for finish full test automatic. The button Single test is use for retest single frequency which is uncertainty. The button Report is use for generator the test result for word format.FM/AM on button is use for searching EUT working frequency.
Picture 3：instruments connection
Picture 4：FM test
Picture 5：AM test
Technical note of BTS system：
- AM，FM interference signal is designed by Matlab software and generated by signal generator model N5182A.
- AM，FM useful signal is generated by model E4421B
- Audio analyzer is carried out by model U8903A.
1：FM，AM interference signal design
Because the interference signal is very difficult designed by analogous circuit. We use the Matlab digital signal process software to design the interference signal.
Frequency response of BS.559 filter designed by Matlab
Frequency response of Pre-emphasis designed by Matlab
Frequency response of 15kHz low pass filter designed by MatlabFrequency response of final interference signal designed by MatlabAM interference signal is similar as above.
One of the most difficult point of this standard is the interference signal design. The interference signal has a big effect of the test result. So we use the profession signal process software Matlab to design it. Frequency response of every step can provide to prove the interference meet the test standard requirement.
Full automatic test, After connection the instruments. without manual action. It save 90% test time than manual test. The automatic test need only 2-3 minutes.