WORK Microwave's Handheld Satcom Test Source

More documents

Recommendations

Info

6 8 10 7 9 6. Now for something completely different. At 75 MHz a signal of -35 dBm is generated and measured with a deviation less than 1 dBm. Absolutely amazing. 7. Since the Deviser S7000 supports two markers in CATV mode which is used to measure the tilt between two channels, I generated one signal at 80 MHz with -35 dBm and a second signal at 100 MHz with -45 dBm. Incredibly, the deviation was -0.1 dBm and -0.2 dBm, respectively. The tilt was measured with 9.9 dB. 8. To test the end of scale I generated a signal at 2000 MHz with -15 dBm. Again the Deviser S7000 measured this signal with an amazing precision. 9. To test the sweep generator several slop step intervals had to be tested in order to allow the spectrum analyzer function to sample enough data to correctly measure the signal. 10. With a slop step interval of 500 ms the Deviser S7000 produced good results so I started the test run. 11. First I measured the whole spectrum with the MAX function active. This way we can see the whole range at the end of the test. The result is excellent with the spectrum oscillating about 3 dB around -35 dBm, which is the output level setup on the Handheld Satcom Test Source. This oscillation is an acceptable error and due to the fact that I was giving the spectrum analyzer just about the time to render the spectrum. 12. This picture shows the same output signal, but this time the signal had to pass a multi switch and about 20 meter of cable, an aerial socket and then another cable before reaching the spectrum analyzer. Notice that only the upper curve is of interest. The result is clear to see: there is an over attenuation of about 10 dB to 15 dB. Also, it is clear to see that the attenuation is not uniform. 11 12 and is the result of the application of international standards in development and production. The pictures show the measured values in the ranges 50 to 180 MHz and 950 to 2150 MHz. These are definitely within the precision range of the device and the tolerance given in the WORK Microwave Handheld Satcom Test Source‘s certificate. This shows that the Handheld Satcom Test Source can be used in another outstanding way: it can be used to precisely calibrate test equipment. Testing a CATV Cable Run Another application for the Handheld Satcom Test Source is the testing of a CATV network‘s cable installation. For this test we used our own distribution network here in the TELE-audiovision test center. A multiswitch with 16 inputs for the satellite range (950 - 2150 MHZ) and another input for terrestrial TV (50 - 850 MHz) was used for distribution. The signal is then made available on eight outputs and distributed throughout the house to a number of antenna ports that each provide separate satellite and CATV outputs. The next step was to measure the attenuation of the signals in the satellite range, but we also wanted to know if the multiswitch, the coax cable and the antenna jacks had more of an affect on some frequencies than on others. Normally, you’d use a noise generator for this task but they typically don’t come with the same measurement precision as does the Handheld Satcom Test Source. If you’re thinking now that it would be an enormous amount of work in that you’d have to check each frequency individually, you’d be wrong. WORK Microwave incorporated a sweep generator in the Handheld Satcom Test Source that can be set to run through a userdefined frequency range (50 to 180 MHz and 950 to 2150 MHz). The frequency steps can also be set (minimum of 0.5 MHz) as well as the desired speed (starting at 10 ms per step). The output level can be set from -5 to -45 dBm. The sweep itself can be run bidirectionally: when the sweep reaches the upper frequency limit, it turns around converter (part number 08590-60090) designed for the 1 MHz to 1.8 GHz range was used. This converter has an attenuation of -15 dBm. The WORK Microwave Handheld Satcom Test Source shows here that this professional signal analyzer can perform measurements with a deviation of less than 1 dB. This is extremely low 106 TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine — 11-12/2013 — www.TELE-audiovision.com www.TELE-audiovision.com — 11-12/2013 — TELE-audiovision International — 全球发行量最大的数字电视杂志 107
and goes back the other way whereby the frequency steps (MHz) and sweep speed (ms) can be set up separately. You can also set up a pause between the two sweeps. The Handheld Satcom Test Source was connected to the input of the multiswitch which would then operate the switch using the frequency sweep generator. The spectrum analyzer mode was activated on the test equipment and it was used with the peaklevel hold function activated in order to be able to read the results of the frequency sweeps across the entire frequency range. The first attempt failed because we didn‘t realize that the spectrum analyzer needs a certain sampling period to be able to generate a spectrum from the signal. If the signal generator sweep is too fast, it doesn‘t allow enough time for the analyzer to correctly measure the signal. So we first had to directly connect the signal generator to the analyzer and try a few different scenarios to determine the correct parameters for the frequency sweep. It quickly became clear why WORK Microwave incorporated so many parameters in the Handheld Sat- ■Setup to measure the attenuation and other problems in our SAT and CATV distribution system. Luckily, the Handheld Satcom Test Source works on battery. 108 TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine — 11-12/2013 — www.TELE-audiovision.com
Page 1 and 2: TEST REPORT Test Signal Generator W
Page 3 and 4: 1 power supply input (12V- 24V), tw
Page 5: y two additional details: a recharg
Page 9 and 10: DAB+ and FM yet with the matching d

WORK Microwave's Handheld Satcom Test Source

Create successful ePaper yourself

Delete template?

Save as template?