Glenayre Electronics Inc. GL-T8600-CN Manuel D’Utilisation
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: 6-9
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An electrically-erasable read-only memory (EEPROM) permanently stores transmitter
signal parameters.
signal parameters.
6.5.2
Digital-to-Analog (D/A) Converter
A D/A converter generates an AGC reference voltage. The D/A converter inputs are data
and select logic. The data, supplied by the MCU when the D/A is selected, represents the
desired transmitter power output. The D/A converter output is an AGC reference voltage.
This voltage represents a level proportional to the desired transmitter power output. The
AGC reference voltage, output through connector J6, is used by the PA to generate an AGC
voltage.
and select logic. The data, supplied by the MCU when the D/A is selected, represents the
desired transmitter power output. The D/A converter output is an AGC reference voltage.
This voltage represents a level proportional to the desired transmitter power output. The
AGC reference voltage, output through connector J6, is used by the PA to generate an AGC
voltage.
6.5.3
8/16-Bit Converter
An 8/16-bit converter allows the MCU eight-bit data bus to communicate with the 16-bit
data bus of the DSP modulator circuit. The MCU must perform two read or write proce-
dures, a low byte and a high byte, to each one of the DSP modulator circuit. The converter
provides two status outputs to the MCU and the DSP modulator circuit. A data-available-
to-MCU status indicates that the DSP modulator circuit has written data into the converter
that the MCU must read. A data-available-to-DSP status indicates that the MCU has written
data into the converter that the DSP modulator circuit must read. In the event that the DSP
modulator circuit does not read data that the MCU has written, a DSP communications fault
is generated.
data bus of the DSP modulator circuit. The MCU must perform two read or write proce-
dures, a low byte and a high byte, to each one of the DSP modulator circuit. The converter
provides two status outputs to the MCU and the DSP modulator circuit. A data-available-
to-MCU status indicates that the DSP modulator circuit has written data into the converter
that the MCU must read. A data-available-to-DSP status indicates that the MCU has written
data into the converter that the DSP modulator circuit must read. In the event that the DSP
modulator circuit does not read data that the MCU has written, a DSP communications fault
is generated.
6.5.4
Read-Only Memory
A programmable and erasable read-only memory (PEROM) stores the control program for
the transmitter. This program is transferred to the MCU when the exciter is booted up. The
nonvolatile PEROM retains its program for years. Its memory may be individually repro-
grammed without erasing the entire chip.
the transmitter. This program is transferred to the MCU when the exciter is booted up. The
nonvolatile PEROM retains its program for years. Its memory may be individually repro-
grammed without erasing the entire chip.