Tektronix TekRanger 2 TFS3031, Service Manual

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Theory of Operation
2–2
TFS3031 TekRanger/TekRanger 2 Service Manual
Theory of Operation
The TFS3031 consists of the following major components:
H
User interface
Keypad
Liquid-crystal display (LCD)
Floppy-disk drive
Serial port
Parallel port
Singlemode optical port (optional)
Multimode optical port (optional)
Keyboard
H
Battery
H
External power port
H
Internal printed circuit boards
Singlemode data-acquisition system (SMDAS) board (optional)
Multimode data-acquisition system (MMDAS) board (optional)
Power-supply board
Main board
LCD backlight power-inverter board
The SMDAS and MMDAS boards contain the optical components, laser drivers,
detector amplifiers, data-acquisition hardware, high-voltage supplies, and
acquisition processors. The processors on the SMDAS and MMDAS boards fire
the lasers, collect waveform data, and communicate with the main board.
Commands from the main board tell the SMDAS and MMDAS boards what
settings to use and when to collect waveform data. The SMDAS and MMDAS
boards then collect the waveform data and send the waveform data back to the
main board over a serial interface.
The main board contains calibration constants for the SMDAS and MMDAS
boards. Therefore, a software-calibration command must be performed if the
main board, SMDAS, or MMDAS board is replaced.
The power-supply board provides power for all the boards. The power-supply
board also supplies the communications channel between boards. The micropro-
cessor on the power-supply board controls battery charging, beeper support, LCD
backlight, LCD contrast, and the front-panel LEDs. This board monitors the
battery voltage, temperature, and current flow continuously to predict remaining
battery capacity and to adjust the charge rate for best performance.
Data Acquisition Boards
Power-Supply Board