VITESSE

SEMICONDUCTOR CORPORATION

Advance Product Information

VSC7710

Photodetector/Transimpedance Amplifier

Family for Optical Communication

G52139-0, Rev 2.2

Page 7

04/02/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

Notes on Measurement Conditions and Applications

Note 1: Noise Measurement Method

The noise voltage, Vn, at the output is referred back to the noise power at the input through the respon-

sivity R (with R in volts/watts)

The bit error rate can be expressed as:

For a

the parameter Q = 7

The sensitivity(s) at a bit error rate of

is calculated as follows:

where the NEP is in units of milliwatts and S is in dBm, respectively.

DUT

Board

3GHz BW

Hybrid Coupler

HP 437B

with

8481D

Power Sensor

Power Meter

RMS

Output

Noise

The noise voltage, (Vn), is calculated from the Output Noise Power, (Pn), into 50 ohm.

Vn

Pn

50

•

=

NEP

Vn

R

-------

=

BER

1

12

–

×10

=

1

12

–

×10

)

NEP

1mW

,

/

2)

√2πQ