Specifications

3-28 888-2857-001 5/9/13
WARNING: Disconnect primary power prior to servicing.
Section 3 Operation
Platinum VAX-C Series
3.4.3.1 Nonlinear Correction Range Setup
The modulator occasionally generates peaks as high as 18 dB above the average output
level. The signal peak power above the average signal power level can be limited at the
modulator output by proper setting of the Nonlinear (Correction) Range. Since this
limitation takes place before the RTAC correction circuitry, only the range of magnitude
RTAC Profiles: Profiles are used to tune the RTAC for various linear and nonlinear operating
conditions. Profile choices for linear and non-linear correction are available. The correct profile will
improve RTAC performance.
Linear Drop menu and select: Basic, Short, Long, Max, Basic Offset, Short
Offset, Long Offset, Max Offset.
Nonlinear Drop menu and select: Basic, Basic Memory, Profile3, Profile 4, High,
High Memory, Profile 7, Profile 8, Profile 9.
Mode Selected after AC Mains Loss
Linear Linear: Drop menu and select: Bypass, Adapt, Stored
Nonlinear Nonlinear: Drop menu and select: Bypass, Adapt, Stored
RTAC Operating Modes During Power Up: When the VAX-C is powered down, RTAC correction for the
Adapt and Hold modes is lost, but the stored RTAC corrections are not lost. At power up, the transmitter
must operate uncorrected for a few minutes while RTAC adapts. If RTAC power on mode is set to
Stored, and if an appropriate correction setup has been previously stored in memory, the Stored
correction will be loaded into the RTAC Adapt and Hold circuits. This correction will then become
available for the LPU RTAC off air Hold mode or for the Adapt mode if the unit is on the air.
Power On Linear Mode The RTAC Power On Linear Mode selection gives the option of having
the exciter's linear RTAC correction in the Adapt, Stored, or Bypass mode
when the exciter is powered on. In the Stored mode, RTAC settings are
obtained from previously stored values from one of the filter sets in the
Stored Correction Sets sub window.
Power On Nonlinear
Mode:
The RTAC Power On Nonlinear Mode selection gives the option of
having the exciter's nonlinear RTAC correction in the Adapt, Stored, or
Bypass mode when the exciter is powered on. In the Stored mode, RTAC
settings are obtained from previously stored values from one of the filter
sets in the Stored Correction Sets sub window.
Frequency Response Tilt Enter value in dB.
Softkeys
Setup Displays Setup screen.
Exciter Home Displays Exciter Home screen.
Table 3-14 Xmtr Home>Exciter Home>Setup>DUC/RTAC>Next & >Next
Field Explanation