noise specifications

understanding noisefive parameters commonly used to specify noise

1. Output LevelDepending on system type and application, there are many different ways to specify output power when choosing a noise product: power, dBm/Hz, dBm/band, ENR, V/ Hz, noise temp °K. 2. Output CharacteristicsIt's important to define:Impedance: common levels are 50, 75, 600 ohms and 1 Kohm.Match: When the noise source is not buffered from other system components, a well-matched noise source (less than 2:1 VSWR) is recommended.Frequency:Choose either bandwidth limited or broadband. 3. Noise CharacteristicsSpecify the following:Peak factor (crest factor): the peak to RMS voltage ratio.Symmetry: uniformity of positive and negative excursions.Power distribution (white): relates how the noise power is distributed in separate components over the frequency range. 4. Input PowerSpecify the following:Voltage: There are many different DC voltages/currents to supply bias to activate the noise source.Control: Noise sources are controlled by the bias or a digital (TTL) interface.Speed: The delay between the control signal and the arrival of the output signal. 5. Accuracy/StabilitySpecify the following:Temperature coefficient: The rate at which the output power changes over temperature.Input sensitivity: The amount of output power changes with variations in input power.Long term drift: The amount of time (in years) it will take the output power to change.Flatness: The peak deviation of power across the frequency range.

Some of the RF & Microwave web site i found

www.miteq.com
www.Microlab.FXR.com
www.minicircuits.com
www.maurymw.com
www.klmicrowave.com
www.kevlin.com
www.cheltonmicrowave.com
www.aeroflex.com
www.tensolite.com
www.rflabs.com
www.mw-elisra.com
www.channelmicrowave.com
www.noisecom.com
www.rfmd.com
www.rlcelecronics.com
www.voltronicscorp.com
www.endwave.com
www.sophiawireless.com
www.cst.com
cst microwave studio
www.ciaowireless.com
www.ansoft.com
nexxim software
www.herotek.com
www.psemi.com
www.berryind.com
www.rogerscorporation.com
www.herley.com
www.Mini-Systeminc.com
www.skyworksinc.com
www.winfoundry.com
www.amlj.com
www.astrolab.com
www.atceramics.com
www.lorch.com
www.synergymwave.com
www.filcs.com
www.rohde-schwarz.com
www.hittite.com
www.sirenza.com
www.nardamicrowave.com
www.spectrum-et.com
www.zcomm.com
www.dilabs.com
www.rtxtech.com
www.vectron.com
www.reactel.com
www.zeland.com
ie3d version
www.eagleware.com
eda
www.sonnetsoftware.com
www.micrometrics.com
www.hubersuhner.com