C

AND

Q

UALITY

A

SSURANCE

Each noise source is accurately calibrated using a reference noise source

traceable to NIST/NPL Calibration data consists of calibration points at 1 GHz intervals

across the fullband*. Data is supplied as a print out. Special calibration data can also be

supplied upon request (consult factory).

Standard choices are:

• More calibration points across the spectrum

• Special discrete calibration frequencies

• Data supplied in soft format as screen capture or text file on

floppy or CD-ROM

In addition to the calibration data, a certificate of calibration and a certificate of

conformance is supplied with each unit.

* 100 MHz intervals for the NSL-2

U

SING

N

OISE

F

OR

B

UILT

-I

N

-T

EST

There are three primary uses for employing a noise signal for built-in-test.

1. 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 determined. By knowing the ENR and Y-factor, one can

calculate noise temperature (figure) or sensitivity.

2. 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.

3. Amplitude Reference Source:

The noise source can be used as a known refer-

ence 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 to test/calibrate its chain as well as the RF.

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

QUATIONS

Calculating Y-Factor:

Calculating Noise figure from ENR and Y-factor:

Converting ENR to Noise spectral density (N

0 dB ENR = -174 dBm/Hz

Calculating noise power in a given bandwidth (BW) from noise spectral density:

H

OW

T

O

O

RDER

N S X X X X - X

Model

Bias Voltage

A = +28V

B = +15V

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