- ページ 4
計測機器 Ceyear 4024DのPDF メンテナンス・マニュアルをオンラインで閲覧またはダウンロードできます。Ceyear 4024D 19 ページ。 Spectrum analyzer
ページを印刷する
Working principle
The 4024 series spectrum analyzer consists of 4 mutually independent function modules with standard
interfaces, namely microwave/millimeter-wave frequency conversion module, frequency synthesis
module, IF signal processing module, and data processing, display and control module. Such a design
facilitates maintenance of the main unit and replacement of the parts, and also significantly reduces the
re-debugging workload of the main unit after the module replacement. The hardware scheme of the main
unit is as shown in Fig. 1.
Input
Program
mable
attenuator
2.1 Microwave/Millimeter-Wave Frequency Conversion Module
It is mainly used for receiving and down-conversion of the input signals of the microwave and
millimeter-wave frequency band. The input signals will enter the frequency conversion module through
the blocking module and 50 dB programmable step attenuator. The RF signals of 9kHz ~ 20 GHz and
broadband local oscillator signals of 6 GHz ~ 12 GHz (or its second harmonic) are mixed to produce
three second IF signals, namely 6,540.25 MHz of the first band (RF frequency is 9 kHz ~ 5.35 GHz),
1,740.25 MHz of the second band (RF frequency is 5.35 GHz ~ 13 GHz) and 3,340.25 MHz of third band
(RF frequency is 13 GHz ~ 20 GHz), and then output 140.25MHz IF signal to the IF channel plate
through down-conversion of the third-stage mixer. The signals above 20 GHz frequency band are mixed
with the first LO signal after the preamplifier and subsection switching filter to produce first IF signal (5
GHz ~ 16.5 GHz).The first IF signal and RF signals of 9kHz ~ 20 GHz are switched into the
second-stage mixer after switching by a single-pole double-throw switch, and the frequency conversion
scheme is the same as the 5 GHz ~ 16.5 GHz. The microwave/millimeter-wave frequency conversion
module directly affects the frequency conversion loss, noise factor, image frequency and off-band signal
suppression and gain compression of the main unit, which consists of the broadband
microwave/millimeter-wave switch, low-noise broadband preamplifier, high performance broadband
microwave/millimeter-wave mixer, microwave/millimeter-wave switch filter module, low power
consumption LO amplifier and multiplying circuit and microwave switch filter module.
2.2 Frequency Synthesis Module
Microwave/millimeter-
wave
Millimeter-wave
downconverter
Multiplying filter
Frequency synthesis
First local
oscillator
Reference ring
Decimal ring
Sampling ring
Data processing, display and
Microprocessor
Power supply
management
Keyboard
Fig. 1 Diagram of Hardware of the Main Unit
frequency
Second
Low-pass filter
-stage
mixer
Switch filter
Second
-stage
mixer
Switch filter
Second
-stage
mixer
module
VCO ring of
the second
local oscillator
control module
FPGA
LCD
Filter
IF amplifier
Filter
IF amplifier
Filter
IF amplifier
Second and third
local oscillators
Fourth local
oscillator
Third
-stage
mixer
Third
-stage
mixer
IF amplifier
Filter
Four-wave
mixer
A D