Shure UC2, Руководство по обслуживанию

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Shure UC2 Hand-Held UHF Transmitter
Service Procedures 11 25A1044 (RI)
Service Procedures
Measurement Reference
dBu is a measure of voltage, and dBm is a measure of power.
For example, the HP8903 should be labeled dBu instead of dBm
because it is a voltage measurement. These two terms are often used
interchangeably even though they have different meanings.
Audio levels in dBu are marked as dBm on the HP8903.
dB Conversion Chart
0 dBV = 2.2 dBu
0 dBu = 0 dBm, assuming the load = 600
Ω
Test Equipment
Most test equipment needed is described in the Shure Wireless
Service Equipment Manual. The following test equipment (or approved
equivalent) is also needed.
Table 1
Test Equipment
Equipment Type Model
Audio analyzer *Hewlett-Packard 8903B
Digital multimeter Fluke 87
Rf signal generator Hewlett-Packard 8656B
Frequency counter Hewlett-Packard 53181A
Spectrum analyzer (domestic) Hewlett-Packard 8590L
Spectrum analyzer (JA, JB) Hewlett-Packard 8591E
Shure UC4 receiver Shure UC4
Test head PT1840
Brass ring for use with test head PT1838–Y
BNC to “rocket launch” cable 95C8418–1
*Audio levels in dBu are marked as dBm on the HP8903B.
Test Equipment Set-Up
The alignment procedure is sequential and does not change,
unless specified.
1. Use RG58 or any low loss, 50
Ω
cables for all rf connections.
Use a BNC to “rocket launch” cable for J frequencies.
2. Keep the test cables as short as possible.
3. Include the insertion loss of the cables and connectors for all rf
measurements.
4. Dc voltages may be present at rf test points. As a precaution,
use dc blocks to protect the test equipment