Broadband Coaxial Noise Sources - Micronetics - #1

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http://www.mwireless.com/Noise_Source/Microwave_Broadband.pdf

Micronetics' line of broadband coaxial noise sources are specially designed for easy integration into microwave systems. They are designed to be rugged with excellent long-term stability.

The heart of Micronetics microwave noise

source is a small chip and wire hermetic noise module. This is embedded in the housing with a precision launch to the

coaxial jack. This design is much more stable and rugged than traditional coaxial

noise sources which rely on pill packaged diodes and beryllium copper bellow assem­blies which not only are less reliable, but use hazardous materials.

The NST series noise sources all feature an embedded regulated driver which offers

maximum stability of the noise diode RF

circuit.

Micronetics low ENR noise sources feature a large value embedded attenuator ideal for Y-factor tests. The attenuator serves dual purposes of lowering the ENR to i a suitable Y-factor amplitude and also improves both on and off state VSWR which | increases noise figure measurement accuracy. j

Operating Temp: -55 to +95^oC Storage Temp: -65 to +125^oC Supply Voltage: +15 VDC, +28 VDC Temperature Stability: 0.01 dB/°C Ouput Impedance: 50 ohm Peak Factor: 5:1

Micronetics offers other ENR values upon request. The optimum ENR of the noise source is dependant on the expected noise figure of the DUT. If the expected noise figure is high, the measured difference of the off and on noise source states will be too hard to discern accurately with the DUT's comparatively large amount of self generated thermal noise. However if the expected noise figure is very low than using a noise source with too high a level of ENR will cause the two measured values to have such disparate amplitudes that non-linear dynamic range issues may compromise accuracy. Depending on how crucial the measure­ment uncertainty window needs to be, the designer can mathematically calculate the theoretical best ENR. This process can be

exhaustive mathematically. Table 1 indicates a quick rule of thumb for ENR vs. expected noise figure. It should be noted that any path loss between the noise source and DUT must be accounted for. If a 10 dB noise source makes sense for the DUT but there is a 10 dB coupler and 3 dB of insertion loss, than a noise source with a 20 - 25 dB ENR is needed.