2715 Spectrum Analyzer Service Manual 3-1
Theory of Operation
This section describes the 2715 circuitry. The section begins with a functional
description of the major circuitblocks. This is followed by more detailed
descriptions of the circuitry with in each block. While reading these descriptions,
refer to the correspondingdiagrams in Section 9: Diagrams.

Block Diagram Description

The Spectrum Analyzer block diagram containsthe following major blocks:
HAttenuator and Low Pass Filter
H1st Converter
H2nd Converter
HRF Mother Board (3rd Converter)
HVR (VariableResolution Module)
HLog Amplifier
HDisplay Storage board
HCenter Frequency Control
H1st LO Buffer
HMicroprocessor
HSweep
HPower Supply (Deflection)
This is a block diagram description of the Spectrum Analyzer.While reading this
description, refer to Figure 3--1.
NOTE. The power levels noted i n the block diagram between the input and the
Log Amplifier assume a -- 30 dBm (+18.8 dBmV) input level.
The block diagram shows ho w the major sections in the instrument relate. It also
shows the paths of most major signals. Not explicitly shown are the interconnec-
tions between the Power Supply and the circuitblocks, interconnections between
the Sweep board and other majorcircuit blocks, and interconnections between
the Deflection System and othercircuit blocks. (The Deflection System is
located on the Power Supply board.)