YOKOGAWA DL2700 Series

4
4 - 1
SM 700820-01E
PRINCIPLE OF THE OPERATION
Chapter 4 PRINCIPLE OF THE OPERA-
TION
This chapter describes the following tests.
4.1 Introduction
4.2 Analog Section
4.3 Digital Section
4.4 Functions of Each Gate Array
4.1 Introduction
Figure 4.1 shows the block diagram of the analog section in the DL2700 and Figure 4.2
shows that of the digital section in the same instrument.
The entire hardware consists of the analog section which includes the attenuators, buffer
amplifiers, one chip amplifiers, and trigger comparators, and the digital section which
includes multiplexers, A/D converter, trigger circuit, acquisition memories, data pro-
cessing circuit, main CPU, sub CPU LCD control circuit, MO disk drive circuit, Logic
probe I/F circuit, keyboard, printer, etc...
4.2 Analog Section
This section consists of the ATT Board Assembly and AFC Board Assembly.
(1) ATT Assembly.
The ATT Assembly incorporates the three switching circuit blocks, the AC/DC cou-
pling, GND/MEASURE and the attenuator factors, 1/1, 1/10, and 1/100. These switch-
ing circuits are composed by relays. The buffer amplifiers and one chip amplifiers are
also incorporated in the ATT assembly.
The one chip amplifier has the Gain switching circuit (×1 to ×20) and the Low pass
filter circuit (external attached LCR). The output of the amplifier is supplied to the A/D
converter and the Trigger circuit.
The attenuators and the amplifiers implement the 5V/div to 2 mV/div input sensitivities.
However, the 2 mV/div sensitivity is actualized by the same way of 4 mV/div in the
analog section. It is realized by doubling the data from A/D converter in the digital
manner.
The control signals of the relay switching, the filter switching, the voltage of the
amplifiers offset, and the Gain control voltage are supplied by the Analog Front-end
controller on the AFC Board Assembly.
One ATT Board Assembly is composed for two channels.
4.1 Introduction