BNC PB-5 - Manual (Page 5)

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factors from 1 to 1000.
Factory testing and calibration is provided via an external tester. A multi-pin connector
separates the µC from the analog circuits. Normally they are connected together by this
multi-pin plug. When the plug is removed a cable can be inserted from an external
tester which provides the functions of the µC. In conjunction with this mode of
operation a test socket, connected to vital circuit points, collects data that can be used by
an external test computer. The tester can automatically find the calibration points to be
placed in the µC memory.
1.3 FUNCTION OF CONTROLS AND CONNECTORS
The spinner knob is an optical encoder capable of slow or fast adjustments. Fine
adjustments are made when the knob is rotated slowly. When the knob is rotated fast
the parameter will change rapidly. Push the knob to make selections from the menu,
rotate to desired value, and push again to select the value. To operate from the keypad,
use the up/down keys and press the ENTER key to select.
The menu is easy to use since there are only two levels. To return to the main menu use
the key on the keypad so marked, or push the spinner knob when in main menu position.
One can use a combination of key pad and spinner knob or operate entirely with the
spinner.
The ENTER key will allow sequential step selection of rise time, fall time, and
attenuation. These are discrete values and therefore not entered with a specific value on
the key pad (can also be selected with the spinner). Pulse amplitude is adjustable in
increments of about 150 µV (better than 1 part in 64,000). Since this amplitude
adjustment is very fine it will take many turns of the spinner knob to cover the 0 to 10
volt range (even with fast rotation). Therefore, when covering a large amplitude range it
may be expedient to enter the number with the keypad and then make any fine
adjustments with the spinner.
The CLAMP mode is not a baseline restorer. Rather it allows long tail pulses to
maintain the same amplitude as rep-rates exceed the duty cycle necessary for full
exponential decay to the baseline. This is accomplished by clamping the tail to the
baseline prior to the next pulse. This may be useful in some applications where the long
tail must be preserved. For optimum performance in this mode the delay must be set
greater than 3.0 µs (see Section 1.5.4).
Three BNC connectors are located on the front panel. The PULSE OUT is reverse
terminated in 50
and provides 0 to10 volts out (0 to 5 volts into 50 ). The EXT
TRIG is used in conjunction with the menu to trigger the pulser at a given threshold and
frequency up to 500 kHz. The TRIG OUT can be used to trigger a scope, another
pulser, or system under test.
When remote operation is desired connect a null modem RS-232 cable to a PC running
PB5 HOST program, a PC running HyperTerminal program, or to a standard terminal.
From the main menu set the PB-5 to remote operation. For operation via PB5 HOST,
refer to Section 3 of this manual. For operation via HyperTerminal select PROPERTIES
from the HyperTerminal file menu to enter the following setup values):