10 GHz Noise Source Opens Eyes
By Ed Garcia, President, NoiseWave Corp

The relentless pursuit of faster, bigger, stronger occurs in all fields and walks of life. From athletics, where records seem to fall daily, to advanced technology that progresses at a bewildering and eye-opening rate, mankind is consistently pushing the envelope. Driven by the need for more and more information, accessed faster and faster, this race can be seen in today’s advanced networking standards and early development of tomorrow’s.

The Ethernet has progressed into the networking standard that currently drives the majority of local computer networks. The criticality of insuring that today’s latest components work seamlessly with each other and tomorrow’s is a key component of standardization and requires the collaboration of leaders in the communication and electronics industry.

Standards such as IEEE802.3ae ensure the interconnectivity of 10 Gigabit Ethernet by requiring stressed receiver sensitivity testing of high speed serial networking communications. Noise based testing is commonly specified because performing in an environment with a certain amount of noise is a fundamental requirement for operation of any communication system. Additionally, noise sources can simulate a variety of operational and environmental stresses.

IEEE802.3aq calls out testing Ethernet based components with a broadband 10 GHz noise source, among various other tests. Fortunately, one now exists that is readily available. The NW10G-M (Figure 1) from NoiseWave Corp is ideal for this application. Following the standard, this noise source can be used to both provide jitter and a random voltage to “stress the eye” and help test interoperability.

Featuring white Gaussian noise from 10MHz to 10 GHz, the NW10G-M outputs -17 dBm minimum power. Internal regulation is standard and the unit operates from +15 Vdc typically drawing 180 mA. The NoiseWave NW10G-M comes standard with a sma output connector and is in a small low profile housing, 4" x 1" x 0.5". Alternative voltages, output levels and frequencies are also available.

Designed for a crest factor of greater than 10:1, this unit is ideally suited for the high speed serial testing and stressing required for 10 GB Ethernet applications. High crest factor is important as this is a key feature of AWGN (Additive White Gaussian Noise) based testing. All Bit-Error-Rate theoretical calculations in the presence of AWGN are based on the Gaussian distribution, and if the noise source does not have a high crest factor, erroneous and often too favorable results will occur.

In the past, bandwidths this large presented a problem for manufacturers of noise sources, but with the advance in MMIC technology and the adoption of sound RF/microwave design and manufacturing processes, this is no longer an issue. Noise modules such as the NW10G-M are now economical and reproduceable; they are typically available in stock to 2 weeks ARO.

- Often times it is convenient in a test or qualification environment to utilize test apparatus that is in a test equipment format rather than a module, which must be mounted in some fashion and supplied power. Fortunately, 10 GHz noise sources in an instrument platform are now standard. The NW10G-MI Manual 10 GHz Noise Instrument is one such convenient solution. Featuring at least -10 dBm of output power, it also provides broad band white Gaussian noise with a high crest factor. Operating from the line voltage offers the user great convenience. Equipped with a front panel rotary precision step attenuator, the user can easily vary the output level and properly test a range of high speed communication devices.

The NW10G family of noise sources is ideal because they can also be used to test virtually all applications besides 10 Gigabit Ethernet. The NoiseWave NW10G-M can be deployed in built in test equipment, for dithering to increase the dynamic range of wideband A/D converters, in UWB test, as a simulation of broadband signals and as an economical source for bit-error-rate (BER) and signal to noise ratio testing. The NW10G family can be employed in virtually all wireless, CATV, satellite and broadband high speed data test applications.

.The wide bandwidth of these noise sources makes them practically future proof. That is, of course, until 100 Gigabit Ethernet comes to pass. NoiseWave, of course, will be there to provide noise sources with the additional bandwidth when required; after all, the race to the future never stops!

NOISEWAVE
www.noisewave.com
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