Service Procedures; Measurement Reference; Test Equipment Setup - Shure UC1L Service Manual

Service Procedures

Measurement Reference

Test Equipment
Test Equipment Set-Up
25A1043 (RI)
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
Most test equipment needed is described in the Shure Wireless
Service Equipment Manual . The following test equipment (or approved
equivalent) is also needed.
Test Equipment
Equipment Type
Audio analyzer
Digital multimeter
Cable
Frequency counter
Rf signal generator
Spectrum analyzer
Shure UC4 receiver
*Audio levels in dBu are marked as dBm on the HP8903B.
The alignment procedure is sequential and does not change,
unless specified.
1. Use RG58 or any other low-loss, 50 Ω test cables for all
rf connections. For JA, JB frequencies, use an adapter cable.
2. Keep the test cables as short as possible.
3. Include the insertion loss of the cables and the connectors
for all rf measurements.
4. Dc voltages are present at most rf test points. Use dc blocks
to protect the test equipment, if necessary.
11
Shure UC1 Body-Pack UHF Transmitter
Table 1
Model
*Hewlett-Packard 8903B
Fluke 87
PT1843
Hewlett-Packard 53181A
Hewlett-Packard 8656B
Hewlett-Packard 8590L
Shure UC4
Service Procedures