Tektronix RTX100A, Service Manual

Page: 76 / 160

Adjustment Procedures
4-2
RTX100A ISDB-T RF Signal Generator Service Manual
Carrier Leakage Adjustment
Perform the following procedure to adjust the carrier leakage:
1. Use the 75
Ω
BNC(Ma)-to-NC(Fe) adapter, 50
Ω
N(Fe)-to-75
Ω Ν ( Μ
a)
adapter, 50 Ω SMA cable, and two 50 Ω N(Ma)-to-SMA(Fe) adapter to
connect the RF Out connector on the RTX100A to the RF Input on the
spectrum analyzer. See Figure 4-1.
RTX100A rear panel
Spectrum analyzer (E4402B-COM)
50
Ω
SMA cable
50
Ω
N(Ma)-to-SMA(Fe)
adapter
50
Ω
N(Fe)-to-75
Ω
N(Ma) adapter
75
Ω
BNC(Ma)-to-
NC(Fe) adapter
50
Ω
N(Ma)-to-SMA(Fe)
adapter
Figure 4-1: Equipment connection for adjusting the carrier leakage
2. Set the spectrum analyzer settings as indicated below:
CENTER FREQ 479.143 MHz . . . . .
FREQ SPAN 15 MHz . . . . . . . .
RBW 30 kHz . . . . . . . . . . . . . .
VBW 300 Hz . . . . . . . . . . . . . .
SWP Speed 0.5 s (Meas Uncal) . . . . . . . . .
REF Level 0 dBm . . . . . . . . . .
ATT 10 dB . . . . . . . . . . . . . . .
3.
Select
ISDB-T/ASI
>
Calibration
on the RTX100A. The
ISDB-T
Calibration Password dialog box appears.
4.
In the dialog box, enter
rtx100cal
for a password. The
ISDB-T Calibration
dialog box appears.
5. In the dialog box, set Reference Frequency to 13 .
6. Set DAC(I) Gain and DAC(Q) Gain to 15 .
7. Select the Cal Signal check box.
Procedure