H

O

O

RDER

R F N 5 5 X -X

Model

L = L band *

S = S band *

C = C band

C1 = C band

C2 = C band

X = X band

Option

0 = Plain

1 = Coax Isolator

2 = Waveguide

3 = Waveguide Isolator

There are several primary uses for employing a noise signal for built-in-

test.

1. Using Noise for Built in Test:: These high output moduels are ideal

for buidl-in-test wehrer there is a significant path loss between the noise

source and the point at which the noise signal is used. For an example

an 8-way splitter in an array antenna receiver will allow enough power at

the receiver plane at each of the eight receive paths. Another example

allows a high directivity coupler to be used (i.e., 30 dB) allowing better

receiver noise figure.

2. Noise Temperature (noise figure) or Sensitivity Testing: This test

uses the noise source to supply a known excess noise ratio (ENR) to a

device under test for a Y-factor measurement. By taking two receiver

readings, one with the noise on and one with it off, Y-factor can be deter-

mined. By knowing the ENR and Y-factor, one can calculate noise tem-

perature (figure) or sensitivity.

3. Frequency Response: The noise source being broadband can be

used as a replacement of a swept source to calculate frequency

response of a receiver or other device. By putting in a known spectral

signal at the input and taking a reading at the output, one can determine

the gain or loss over frequency of the entire system. Noise sources are

inherently extremely stable devices. In addition, the circuitry is much

simpler than a swept source which increases reliability and lowers cost.

4. Amplitude Reference Source: The noise source can be used as a

known reference signal. By switching in the noise source from the live

signal, a quick test can be performed to check the health of the chain or

calibrate the gain/loss. For this test, noise can be injected into the IF

system as well as the RF to test/calibrate the path.

For more information on using noise for built-in-test, read the Feb 2004

Microwave Journal article authored by Patrick Robbins of Micronetics.

http://www.micronetics.com/articles/microwave_journal_02-04.pdf

U

SEFUL

N

OISE

E

TIONS

Calculating Y-Factor:

Calculating Noise figure from ENR and Y-factor:

0 dB ENR = -174 dBm/Hz

Calculating noise power in a given bandwidth (BW) from noise

spectral density:

* waveguide not

available on S

and L models