Tektronix DSA8200 Series, Руководство по обслуживанию

Страница: 41 / 196

Theory of Operation
DSA8200 Digital Serial Analyzer and Modules Service Manual
2- 7
The recovered clock is routed in coaxial cable through the rear connector of the
module to the Optical Front End board in the mainframe. The Optical Front End
board has a switch that selects which modules clock will be applied to the
trigger. The control signal for that switch comes from the optical module.
The 80C01 module supports conformance testing of long wavelength
(1100-1650 nm) signals at 622, 2488, and 9953 Mb/s as well as general purpose
testing up to 20 GHz optical bandwidth. Bandwidth and reference receiver
calibration is performed with a sub-picosecond optical impulse and a fourier
transform method.
1
OC12: The electrical sampler is adjusted to approximately 7.5 GHz (--3 dB)
bandwidth and signal is routed through a hardware filter designed to result in
the combined system having an OC12 (STM-4) Reference Receiver
response.
1
OC48: The electrical sampler is adjusted to 7.5 GHz (--3 dB) bandwidth and
signal is routed through a hardware filter designed to result in the combined
system having an OC48 (STM-16) Reference Receiver response. These
adjustments must be made at the factory.
1
OC192: The electrical sampler is adjusted to give the desired response, and
signal is not routed through any filter (signal is sent through the straight-
through path). The sampler bandwidth and response is optimized during the
calibration such that the combined system will have an OC192 (STM-64)
Reference Receiver response.
1
12.5 GHz: The sampler bandwidth and response is set during the calibration
such that the combined system will have an Optical Bandwidth (--6 dB)
>12.5 GHz.
1
20 GHz: The sampler bandwidth and response is set during the calibration
such that the combined system will have an Optical Bandwidth (--6 dB)
>20 GHz.
The 80C02 module is optimized for testing of long-wavelength (1100-1650 nm)
signals at (9.953 Gb/s) SONET OC-192 / SDH STM-64 standards. With its high
optical bandwidth (>30 GHz) it is also well suited to general purpose high-per-
formance optical component testing.
1
OC192: The electrical sampler is adjusted to give the desired response, and
signal is not routed through any filter (signal is sent through the straight-
through path). The sampler bandwidth and response is optimized during the
calibration such that the combined system will have an OC192 (STM-64)
Reference Receiver response.
80C01 Optical Sampling
Module
80C02 Optical Sampling
Module