Optical Sampling Modules
CSA8000 & TDS8000 Instruments and Sampling Modules
4–89
therefore at
–3 dB
V
f
V
DC
+
0.707
In the CSA8000 and TDS8000 instruments, the vertical units displayed for an
optical module are not in voltage, but are in watts, which is a unit of power. The
O/E converter inside the module outputs a voltage swing whose amplitude is
linearly dependent on the incoming optical power swing. In this condition the
voltage applied at the electrical sampler already represents Optical Power in its
linear form (as opposed to having to square the voltage and divide by R). For the
optical sampling modules, then, the bandwidth where the displayed optical
power is one half that approaching DC is:
dB
+
10
log
ǒ
Power
f
Power
DC
Ǔ
+
–3 dB
The V
f
in such a system is one half (0.5) the V
DC
as opposed to 0.707. The
optical bandwidth, therefore, corresponds to the traditional electrical bandwidth
at –6 dB. During testing of optical modules via impulse testing, the resulting
impulse waveform is converted to frequency via Fourier transform, and the
bandwidth is defined as:
*
3 dB
+
10
log
ǒ
vertical swing @ frequency
vertical swing @ DC
Ǔ
This definition is used for 2.5 GHz, 12.5 GHz, 20 GHz, and 30 GHz bandwidth
settings.
During reference receiver curve calculation, however, the definition is changed to
match the industry standard definition, which was authored assuming electrical
bandwidths where:
*
3 dB
+
20
log
ǒ
vertical swing @ frequency
vertical swing @ DC
Ǔ
This definition is used for reference receiver settings OC12, OC48, OC192,
GBE, 2
GBE and FC 1063.
Содержание CSA8000 Series
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Страница 18: ...Service Safety Summary xiv CSA8000 TDS8000 Instruments and Sampling Modules ...
Страница 22: ...Preface xviii CSA8000 TDS8000 Instruments and Sampling Modules ...
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Страница 59: ...80C00 Modules Specifications 1 36 CSA8000 TDS8000 Instruments and Sampling Modules back ...
Страница 63: ...80A01 Module Specifications 1 40 CSA8000 TDS8000 Instruments and Sampling Modules ...
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Страница 74: ...Installation 2 10 CSA8000 TDS8000 Instruments and Sampling Modules ...
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Страница 103: ...Theory of Operation 3 10 CSA8000 TDS8000 Instruments and Sampling Modules ...
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Страница 106: ...Performance Verification Procedures 4 2 CSA8000 TDS8000 Instruments and Sampling Modules ...
Страница 122: ...Brief Procedures 4 18 CSA8000 TDS8000 Instruments and Sampling Modules ...
Страница 126: ...Performance Tests 4 22 CSA8000 TDS8000 Instruments and Sampling Modules ...
Страница 218: ...80A01 Trigger Preamplifier Module 4 114 CSA8000 TDS8000 Instruments and Sampling Modules ...
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Страница 231: ...Maintenance 6 6 CSA8000 TDS8000 Instruments and Sampling Modules ...
Страница 291: ...Removal and Installation Procedures 6 66 CSA8000 TDS8000 Instruments and Sampling Modules ...
Страница 307: ...Repackaging Instructions 6 82 CSA8000 TDS8000 Instruments and Sampling Modules ...
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Страница 315: ...Electrical Parts List 8 2 CSA8000 TDS8000 Instruments and Sampling Modules ...
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