The delay is varied to select any specific line in the selected field as the trigger point. Bus Buffers The 1 0-MHz clock signal of the standard oscilloscope is buffered by U4265D. The buffered clock (B10MHZ) clocks the shift register (U4275) and is also sent to the options. Adjust the generator output to produce a 0.5-division display by varying the signal IRE level. dd. CHECK— That the display is triggered and stable. ee. Printed in U.S.A. Specification and price change privileges are reserved. INSTRUMENT SERIAL NUMBERS Each instrument has a serial number on a panel insert, tag, or stamped on the chassis.
When timing measurements are requested while a conflicting Counter/Timer/Trigger (CTT) function is operat- ing, the timing measurement is displayed with the accuracy and resolution associated with the standard oscilloscope not equipped with the CTT Option. Direct measurement capability operates when the B Sweep is triggerable after delay as well as in RUN AFTER DLY. Direct measurement increases resolution and accuracy. When the counters stop, the microprocessor reads the counters and calculates the Delta Time. Pulse-width measurement is made easier by using the B TRIG A DLY mode.
Frequency mode uses Counter A and Counter B. Counter A counts the 131 MHz clock while Counter B counts cycles of the unknown signal. Since detailed operating instructions for the test equipment are not provided in this procedure, refer to the appropriate test-equipment instruction manual if additional information is required. The front-panel SLOPE selector determines whether the amplifier is inverting or noninverting. Pin 1 is always HI, except when the microprocessor is reading data from an option. U4255 is Inactive when pin 19 is HI. Signals on pin 1 and pin 19 coordinate the states of U4255 so that data bus contention never occurs. Buffered address bit 0, through R6222, injects about one cycle of phase jitter into the loop to reduce aliasing effects.