Tektronix P6245, Instruction Manual

Page: 182 / 214

Theory of Operation
4- 2
P6245 Instruction Manual
All signal amplification and buffering is performed in the probe head
assembly. No further amplification takes place in the compensation
box.
Compensation Box
The compensation box contains the following circuits:
H
Offset amplifier
H
Probe identification EEPROM
H
TEKPROBE interface
Offset Amplifier
The offset amplifier is used to offset the input signal’s DC compo-
nent so that it stays at the optimal point of the probe’s linear dynamic
range. For more information on the linear dynamic range characteris-
tic, refer to the notes on page 2--1.
The offset amplifier receives offset information as a
±
1 VDC voltage
from the oscilloscope. The amplfier then amplifies it to match the
probe characteristics and applies it to the probe hybrid circuit.
The offset amplifier has two adjustments: offset zero and offset gain.
These adjustments rarely need attention; however, detailed
adjustment instructions are in the
Adjustment section on page 4--9.
Probe Identification EEPROM
The probe identification EEPROM is used to configure the
oscilloscope to the probe. The EEPROM receives a clock input from
the oscilloscope, and information about the probe is passed to the
oscilloscope.
TEKPROBE
™
Interface
The TEKPROBE interface provides a communication path between
the probe and the oscilloscope. Contact pins provide power, signal,
offset, and data transfer for the probe identification EEPROM.