74 75 TELE-satellite International — The World‘s Largest Digital TV Trade Magazine — 11-12/2012 — www.TELE-satellite.com www.TELE-satellite.com — 11-12/2012 — TELE-satellite International — 全球发行量最大的数字电视杂志 DEVISER AE 120 Optical Power Meter • so simple to use • gives very accurate readings • comes with adapters for all popular connector types • shows levels in very small steps • if needed, it can be calibrated TEST REPORT Fiber Optic Meter
Transcript
74 75TELE-satellite International — The World‘s Largest Digital TV Trade Magazine — 11-12/2012 — www.TELE-satellite.com www.TELE-satellite.com — 11-12/2012 — TELE-satellite International — 全球发行量最大的数字电视杂志
Extremely simle to use but at same time very accurate
76 77TELE-satellite International — The World‘s Largest Digital TV Trade Magazine — 11-12/2012 — www.TELE-satellite.com www.TELE-satellite.com — 11-12/2012 — TELE-satellite International — 全球发行量最大的数字电视杂志
Small Size But Excellent Performance
TEST REPORT Fiber Optic Meter
Fiber optic cables are find-ing their way into digital TV installations more and more often. They are superior to coax cables due to very low attenuation and immunity to electromagnetic interfer-ence. Their advantages are especially striking in larger networks - dedicated for a multistory building or even larger. However, like with the classical coaxial cable networks, the installer must have a suitable tool to meas-ure signal power, even when
dealing with modern optical networks. And because here we are dealing with light rather than electric voltage and current, another type of meter is needed.
The AE 120 Optical Power Meter made by Deviser is a tiny and lightweight meter that you can use not only to confirm that the optical sig-nal is reaching a given node of a network but also to ac-curately measure its power level. Using the AE120, you can find bad fiber optic ca-
TELE-satellite Test Editor Jacek Pawlowski checking the AES120 Optical Meter by Deviser. A DVB-T signal is converted into an optical signal and the results measured with the AES120
ble junctions, i.e. the ones introducing excessive light attenuation, or locate faulty components - like optical splitters.
The AE120 is enclosed in a gray plastic case which is surrounded with a protective holder made of blue rubber. Below a classical LCD dis-play, 6 buttons are located. The input connector can be found on the top side of the case. Thanks to the two ad-ditional adapters included in the set, you can connect the AE120 to any type of optical connector you are likely to find in an optical networks: FC, SC or ST. After taking the meter out of the blue
rubber holder you get access to its rear panel. There is a slide door there securing the battery compartment. Two AA batteries (or AA accumu-lators) can be used. In the set we got for testing, there was also an AC/DC charger included.
The user manual that came along with the AE120 was in the form of a small booklet. And because operating the meter is so simple and intui-tive, we are sure that except for maybe the first time, you will hardly need it. But any-way, the manual is well writ-ten and provides all the infor-mation you might need. The display of the meter shows two values: optical level ex-pressed either in dBm or in Watts, and the wavelength in nanometers the meter is
78 TELE-satellite International — The World‘s Largest Digital TV Trade Magazine — 11-12/2012 — www.TELE-satellite.com
tuned to. It could not be sim-pler!
The AE120 has selectable wavelengths. As you could expect, there are the com-mon 1310 nm, 1490 nm and 1550 nm bands. But not only. One can order additional, user defined wavelengths.
Our test unit had four addi-tional bands: 850 nm, 980 nm, 1300 nm and 1610 nm – so seven in total. The λ but-ton is used to cycle through different wavelengths. On power up, the smallest one is selected (850 nm in our case). You should switch to
the correct wavelength in or-der to get the correct result.
You can easily guess the function of the other but-tons. The dBm/W button is used to cycle the units of the measured power. The REF button is used to store the current measurement
result as the reference level to which you will be able to compare the next measure-ment – most likely - in the other nodes of the network. To store the reference level you press and hold a but-ton for a longer while. An-other short press - and you are back in the normal mode when you measure the pre-sent value.
Having stored a result as the reference, you can press the dB button to express the current measurement with respect to the stored value in decibels. For example, if you had measured in one node a value of +3.66 dBm and stored it as a reference and then moved to another node of the network and meas-ured -3.38 dBm, pressing the REF button would show you -7.04 dB. The meaning of this would be that at the second node the signal was 7.04 dB weaker than in our reference point. In this way, we can conveniently check if the optical splitters located between the two nodes do not introduce too much at-tenuation.
The function of the two remaining button is self-ex-planatory: one turns on and off the back-light of the dis-play and the other is just the power on/off switch. As you can see, once you get famil-iar with this meter, you will never forget how to use it - it is so straightforward and logical.
In order to test the AE120 meter, we used an optical transmitter converting a DVB-T signal into an optical one. We compared the me-ter to another similar tool dedicated for the installers. (graph 1.)
As you can see in the at-tached graph, the results of both meters were quite similar. However, when we attenuated the signal, AE120 was still able to measure it (-19.97 dBm) while its com-
Operation Time (backlight off) 50 hours with two AA bateries
Dimensions 119 x 70 x 29 mm
Weight 200 g without bateries
Jacek PawlowskiTELE-satellite
Test CenterPoland
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www.TELE-satellite.com/TELE-satellite-1107/eng/deviser.pdfMORE ABOuT THIS COMPANy
80 81TELE-satellite International — The World‘s Largest Digital TV Trade Magazine — 11-12/2012 — www.TELE-satellite.com www.TELE-satellite.com — 11-12/2012 — TELE-satellite International — 全球发行量最大的数字电视杂志
petitor displayed just “LOW” message.
That’s because the AE120 has an impressive dynamic range of 68 dB. It can meas-ure optical power from -43 dBm through to +25 dBm.
Moreover, the Deviser AE120 was able to measure power with 0.01 dBm reso-lution while its competitor was not able to discriminate changes smaller than 0.5 dBm.
The AE120 measurement uncertainty is merely ±0.17 dB (±3%) which is an impres-sive figure. Deviser made it possible to re-calibrate the meter if the user has access to laboratory grade equip-ment. It is possible to switch the meter to the calibration mode and enter the correc-tion if needed. The range of the possible correction is from -1 dB to + 1dB. It is de-scribed in the manual how to do that. Also this operation is quite simple to perform.
To sum it up: the AE120 is extremely simple to use but at the same time very accurate and stable. It is a perfect companion for every installer who deals with to-day’s modern fiber optic net-works.
Very handy: small and lightweightExtremely simple to operateSwitchable wavelengthsAvailable reference level measurement modeWide dynamic range and high accuracyAll popular fiber cable connectors supported
The display back-light is rather weak
Expert Opinion
1-6. Do you know the wave-length of your fibre optic system? No problem, measure the same signal for different lambda and the highest read-ing indicates the wavelength; in our case this is evidently 1490 nm because the maxi-mum reading is just for this setting7. After pressing the REF button for 2 seconds, the current level (-0.57 dBm) becomes the reference level8. Now we have switched to reference measurement mode by pressing the dB button9. Measurement results are reffered now to -0.57 dBm10. If you prefer, you may use mW rather than dBm units
Measurements with the DEVISER AE 120 Optical Power Meter
