Glenayre Electronics Inc. GL-T8600-CN Manual Do Utilizador
DSP Exciter
Glenayre Document Number: 9110.00172
OPTIONS
Issue 1, Rev. I: 01/15/97
Page: 10-2
Copyright © 1997 Glenayre
Print Date: 02/19/97
10.1.3.1 Analog-Mode A/D Conversion
The exciter DSP modulator circuit reads synchronized serial data for its analog mode input
signal, but the QT-1000 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.
signal, but the QT-1000 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.
10.1.3.2 FSK-Data-Bit Strapping
The exciter DSP modulator circuit can read up to four bits for its digital FSK mode input
signal, but the controller provides two active bits 1 and 2 (DATA1, DATA2). This allows
transmitter operation in the two-level or four-level mode.
signal, but the controller provides two active bits 1 and 2 (DATA1, DATA2). This allows
transmitter operation in the two-level or four-level mode.
10.1.3.3 Channel-Select-Bit Strapping
The exciter MCU control circuit reads three bits to determine the remotely selected
channel, but the QT-1000 controller provides only bits 1 and 2 (CH SEL 1,2). As a result,
the QT-1000 controller can command only four channels. The controller interface keeps bit
3 open (high).
channel, but the QT-1000 controller provides only bits 1 and 2 (CH SEL 1,2). As a result,
the QT-1000 controller can command only four channels. The controller interface keeps bit
3 open (high).
Table 10-2
defines the transmitter operating channel resulting from the
channel select inputs.
10.1.3.4 Mode-Select-Bit Strapping
The exciter MCU control circuit reads two bits to determine the remotely selected mode,
but the QT-1000 controller provides only bit 1 (MODE CONTROL). As a result, the QT-
1000 controller can command only two modes. The controller interface straps bit 2 to
ground (low).
but the QT-1000 controller provides only bit 1 (MODE CONTROL). As a result, the QT-
1000 controller can command only two modes. The controller interface straps bit 2 to
ground (low).
Table 10-3
defines the transmitter operating mode resulting from the model
select input.
10.1.3.5 Power Sample D/A Conversion
The QT-1000 controller reads two 0-to-2.5-volt voltages for its forward and reflected
power sample inputs, but these power values are stored as data in the exciter MCU control
circuit. The controller interface converts the data to voltages of the appropriate range for
the QT-1000 controller. Data from the MCU representing the forward and reflected powers
is written into a dual D/A converter. The D/A converts the data into two proportional dc
voltages ranging from 0 volt to 2.5 volts (FWD PWR SAMPLE, REF PWR SAMPLE),
which are applied to the QT-1000 controller. Control logic gates ensure that data is written
to the proper half of the D/A converter.
power sample inputs, but these power values are stored as data in the exciter MCU control
circuit. The controller interface converts the data to voltages of the appropriate range for
the QT-1000 controller. Data from the MCU representing the forward and reflected powers
is written into a dual D/A converter. The D/A converts the data into two proportional dc
voltages ranging from 0 volt to 2.5 volts (FWD PWR SAMPLE, REF PWR SAMPLE),
which are applied to the QT-1000 controller. Control logic gates ensure that data is written
to the proper half of the D/A converter.