Glenayre Electronics Inc. GL-T8600-CN Manual Do Utilizador
Glenayre Document Number: 9110.00172
DSP Exciter
Issue 1, Rev. I: 01/15/97
THEORY OF OPERATION
Print Date: 02/19/97
Copyright © 1997 Glenayre
Page: 6-3
sec_
6
6.2
Interface to Controller
6.2.1
General
The controller interface is the portion of exciter circuitry that connects the transmitter
controller to the exciter. The interface board dictates what kind of transmitter controller
may operate the transmitter. The transmitter can be operated through one of several control-
lers depending on which interface board is installed in the exciter. The internal interface
board may also exhibit an external I/O board.
controller to the exciter. The interface board dictates what kind of transmitter controller
may operate the transmitter. The transmitter can be operated through one of several control-
lers depending on which interface board is installed in the exciter. The internal interface
board may also exhibit an external I/O board.
Control commands from the transmitter controller are connected through the interface
circuit. This circuit supplies remote control to the microcontroller unit (MCU) control
circuit. The VT-100 VDT supplies local control. The MCU control circuit generates all
control signals for the other circuits, and monitors their status. The MCU control circuit
reports status back to the VT-100 VDT and the interface circuit, which supplies the status
to the transmitter controller.
circuit. This circuit supplies remote control to the microcontroller unit (MCU) control
circuit. The VT-100 VDT supplies local control. The MCU control circuit generates all
control signals for the other circuits, and monitors their status. The MCU control circuit
reports status back to the VT-100 VDT and the interface circuit, which supplies the status
to the transmitter controller.
6.2.2
Interface Conversion Functions
Some signals exchanged between the controller and the exciter originate with a format,
voltage, or requirement incompatible with their destination. The interface performs any
signal conversions necessary to provide compatibility between the controller and the
exciter. None, some, or all of the following conversion functions may be done by any one
particular interface board.
voltage, or requirement incompatible with their destination. The interface performs any
signal conversions necessary to provide compatibility between the controller and the
exciter. None, some, or all of the following conversion functions may be done by any one
particular interface board.
6.2.2.1
Analog-Mode A/D Conversion
The DSP modulator circuit reads synchronized serial data for its analog mode input signal.
if the transmitter controller provides an analog signal, the controller interface converts the
analog to the appropriate data form for the DSP. The analog (FLAT AUDIO+, -) terminates
across a balanced input circuit that also provides a level adjustment. The adjustment, when
properly set by the AUDIO INPUT ADJUST pot through the exciter cover, provides analog
to an A/D converter at the optimum zero-dBm level. The A/D converts the analog into
serial data, which is applied to the DSP through a synchronous data link. A synchronous
data link is characterized by an exchange of pulse streams for timing purposes. The A/D
converter is clocked by a pulse generator circuit driven by the ten-MHz reference circuit.
if the transmitter controller provides an analog signal, the controller interface converts the
analog to the appropriate data form for the DSP. The analog (FLAT AUDIO+, -) terminates
across a balanced input circuit that also provides a level adjustment. The adjustment, when
properly set by the AUDIO INPUT ADJUST pot through the exciter cover, provides analog
to an A/D converter at the optimum zero-dBm level. The A/D converts the analog into
serial data, which is applied to the DSP through a synchronous data link. A synchronous
data link is characterized by an exchange of pulse streams for timing purposes. The A/D
converter is clocked by a pulse generator circuit driven by the ten-MHz reference circuit.
6.2.2.2
FSK-Data-Bit Strapping
The DSP modulator circuit can read up to four bits for its digital FSK mode input signal. If
the controller provides only bit 1 (DATA 1), operation in the four-level mode or higher is
precluded. Bits 2 through 4 (DATA2 through DATA4) are available as FSK data inputs;
whether they are used or not is a function of the particular controller interface used and the
transmitter controller. Refer to Section 10. The controller interface disables unused bits by
ground straps.
the controller provides only bit 1 (DATA 1), operation in the four-level mode or higher is
precluded. Bits 2 through 4 (DATA2 through DATA4) are available as FSK data inputs;
whether they are used or not is a function of the particular controller interface used and the
transmitter controller. Refer to Section 10. The controller interface disables unused bits by
ground straps.