Mindray DPM5 User manual

Service Manual (V 3.0)

Copyright

Statement

Mindray DS USA, Inc. (hereinafter called Mindray DS) owns all rights to this unpublished work

and intends to maintain this work as confidential. Mindray DS may also seek to maintain this

work as an unpublished copyright. This publication is to be used solely for the purposes of

reference, operation, maintenance, or repair of Mindray DS equipment. No part of this can be

disseminated for other purposes.

In the event of inadvertent or deliberate publication, Mindray DS intends to enforce its rights to

this work under copyright laws as a published work. Those having access to this work may not

copy, use, or disclose the information in this work unless expressly authorized by Mindray DS

to do so.

All information contained in this publication is believed to be correct. Mindray DS shall not be

liable for errors contained herein nor for incidental or consequential damages in connection

with the furnishing or use of this material. This publication may refer to information and

protected by copyrights or patents and does not convey any license under the copyright and

patent rights of Mindray DS, nor the rights of others. Mindray DS does not assume any liability

arising out of any infringements of patents or other rights of third parties.

is a trademark or a registered trademark of Shenzhen Mindray

Bio-Medical Electronics Co., Ltd. All third-party trademarks that appear in this manual are used

solely for editorial purposes and are the property of their respective owners.

Content of this manual is subject to changes without prior notice.

PROPERTY OF Mindray DS USA, Inc.ALL RIGHTS RESERVED

Responsibility on the manufacturer party

Mindray will not be liable for the effects on safety, reliability and performance of this product if:

• any installation, expansion, change, modification and repair of this equipment are not

conducted by Mindray DS qualified personnel;

• applied electrical appliance does not comply with relevant National Standards;

• the monitor is not operated under strict observance of this manual.

Warning

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Service Manual (V 3.0)

For continued safe use of this equipment, it is necessary that the listed instructions are

followed. However, instructions listed in this manual in no way supersede established medical

practices concerning patient care.

z Do not rely only on audible alarm system to monitor patient. When monitoring

adjusting the volume to very low or completely muting the sound may result in the
disaster to the patient. The most reliable way of monitoring the patient is at the
same time of using monitoring equipment correctly, manual monitoring should be
carried out.

z This multi-parameter patient monitor is intended for use only by medical

professionals in health care institutions.

z T o avoid elec trical shock, you shall not open any cover by yourself. Service must be

carried out by qualified personnel.

z Use of this device may affect ultrasonic imaging system in the presence of the

interfering signal on the screen of ultrasonic imaging system. Keep the distance
between the monitor and the ultrasonic imaging system as far as possible.

z It is dangerous to expose electrical contact or applicant coupler to normal saline,

other liquid or conductive adhesive. Electrical contact and coupler such as cable
connector, power supply and parameter module socket-inlet and frame must be
kept clean and dry. Once being polluted by liquid, they must be thoroughly dried. If
to further remove the pollution, please contact your biomedical department or
Mindray DS.

It is important for the hospital or organization that employs this equipment to carry out a

reasonable maintenance schedule. Neglect of this may result in machine breakdown or injury

of human health.

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Service Manual (V 3.0)

Warranty

THIS WARRANTY IS EXCLUSIVE AND IS IN LIEU OF ALL OTHER WARRANTIES,

EXPRESSED OR IMPLIED, INCLUDING WARRANTIES OF MERCHANT ABILITY OR

FITNESS FOR ANY PARTICULAR PURPOSE.

Exemptions

Mindray DS 's obligation or liability under this warranty does not include any transportation or

other charges or liability for direct, indirect or consequential damages or delay resulting from

the improper use or application of the product or the substitution upon it of parts or accessories

not approved by Mindray DS or repaired by anyone other than a Mindray DS authorized

representative.

This warranty shall not extend to any instrument which has been subjected to misuse,

negligence or accident; any instrument from which Mindray DS 's original serial number tag or

product identification markings have been altered or removed, or any product of any other

manufacturer.

Safety, Reliability and Performance

Mindray DS is not responsible for the effects on safety, reliability and performance of the

DPM5 Patient Monitor if:

■ assembly operations, extensions, re-adjusts, modifications or repairs are carried out

by persons other than those authorized by Mindray DS.

■ the DPM5 is not used in accordance with the instructions for use, or the electrical

installation of the relevant room does not comply with NFPA 70: National Electric

Code or NFPA 99: Standard for Health Care Facilities (Outside the United States, the

relevant room must comply with all electrical installation regulations mandated by the

local and regional bodies of government).

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Service Manual (V 3.0)

Return Policy

Return Procedure

In the event that it becomes necessary to return a unit to Mindray DS, the following procedure

should be followed:

1. Obtain return authorization. Contact the Customerr Service Department and obtain a

Customer Service Authorization (Mindray DS) number. The Mindray DS number must

appear on the outside of the shipping container. Return shipments will not be accepted if

the Mindray DS number is not clearly visible. Please provide the model number, serial

number, and a brief description of the reason for return.

2. Freight policy. The customer is responsible for freight charges when equipment is shipped

to Mindray DS for service (this includes customs charges).

3. Return address: Please send the part(s) or equipment to the address offered by the

Customer Service department

Company Contact

Manufacturer: Mindray DS USA, Inc.

Address: 800 MacArthur Blvd. Mahwah, New Jersey 07430 USA

Tel: [phone] 1.201.995.8000

Website: www. mindray.com

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Service Manual (V 3.0)

Safety Precautions

1. Meaning of Signal Words

In this manual, the signal words WARNING and CAUTION are used regarding safety

and other important instructions. The signal words and their meanings are defined as follows.

Please understand their meanings clearly before reading this manual.

Signal word Meaning

WARNING

CAUTION

Indicates a potentially hazardous situation which, if not avoided,
could result in death or serious injury.

Indicates a potentially hazardous situation which, if not avoided,
may result in minor or moderate injury.

2. Meaning of Safety Symbols

Symbol Description

Type-BF applied part

"Attention" (Refer to the operation manual.)

Safety Precautions

Please observe the following precautions to ensure the safety of service engineers as well as

operators when using this system.

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Service Manual (V 3.0)

WARNING: Do not connect this system to outlets with the same circuit

breakers an d fuses that co ntrol current to devices such as
life-support systems. If this system malfunctions and
generates an over current , or when there is an instantaneous
current at power ON, the circuit breakers and fuses of the
building’s supply circuit may be tripped.
Do not use flammable gases such as anesthetics, or flammable
liquids such as ethanol, near this product, because there is
danger of explosion.

CAUTION: 1. Malfunctions due to radio waves

(1) Use of radio-wave-emitting devices in the proximity of this

kind of medical electronic system may interfere with its
operation. Do not bring or use devices which generate radio
waves, such as cellular telephones, transceivers, and radio
controlled toys, in the room where the system is installed.

(2) If a user brings a device which generates radio wav es near the

system, they must be instructed to immediately turn OFF the
device. This is necessary to ensure the proper operation of
the system.

2. Do not allow fluids such as water to contact the system or
peripheral devices. Electric shock may result.

VI

Symbols

Service Manual (V 3.0)

displaying this symbol contains an F-Type isolated (floating) patient applied part providing

a high degree of protection against shock, and is suitable for use during defibrillation.

Equipotential grounding terminal

@ Mark Event 》 Next menu

*** Highest level alarm ** Middle level alarm

* Lowest level alarm

Ð Trend graph cursor u SYS pressure（NIBP trend graph）

t DIA pressure(NIBP trend graph) * MEAN pressure (NIBP trend

graph)

Î Right moving indicator Í Left moving indicator

Be Careful Protective earth ground

Indicates that the instrument is IEC-60601-1 Type CF equipment. The unit

Silence Symbol ！ Close all alarm volume

Alarm pause

Heart beat

× Gain magnify √ Confirm

SN Series Number

VII

Pace signal

FOR YOUR NOTES

Service Manual (V 3.0)

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Service Manual (V 3.0)

Contents

CHAPTER 1 ABOUT THE PRODUCT..............................................................................................1

1.1 INTRODUCTION................................................................................................................................1

1.2 APPLICATION ...............................................................................................................................1

1.2.1 General...............................................................................................................................1

CHAPTER 2 PRINCIPLES ............................ .............................. ........................................................5

2.1 GENERAL ...........................................................................................................................................5

2.1.1 Parameter Measurement....................................................................................................5

2.1.2 Main Control Part............................................................................................ ..................6

2.1.3 Man-Machine Interface......................................................................................................6

2.1.4 Power Supply......................................................................................................................6

2.1.5 Other Auxiliary Functions................................... ............................... ................................6

2.2 HARDWARE DESCRIPTION ..........................................................................................................7

2.2.1 Main Board.........................................................................................................................8

2.2.2 ECG/RESP/TEMP Module........................... ... .... ... .. ..... .. .. ..... .. ... ..... .. ..... .. .. ..... .. ... .... ... .. ....9

2.2.3 CO/IBP Module................................. .... ... .. ..... .. ..... .. .. ..... .. ... .... ... .. ..... .. ... .... ... .. ..... .. .. ..... ..12

2.2.4 SpO2 Module...................................... ...............................................................................13

2.2.5 NIBP Module..................................... .. .. ..... .. ... .... ... .. ..... .. .. ..... .. ... ..... .. ..... .. .. ..... .. ... .... ... .. ..14

2.2.6 Recorder Module............................ ... .. ..... .. .. ..... .. ..... .. ... .... ... .. ..... .. .. ..... ... .. ..... .. .. ..... .. ... ....15

2.2.7 Button Panel.................................................... ............................................................. ....16

2.2.8 Power PCB.......................................................................................................................17

2.3 SOFTWARE DESCRIPTION ........................................................................................................18

2.3.1 General.............................................................................................................................18

2.3.2 System Task................................................. ....... ......... ....... .......... ....... ......... ....... .......... ....19

2.3.3 System Function................ .......................................................................................................20

2.4 SYSTEM PARAMETER................................................................................................................21

2.4.1 General.............................................................................................................................21

2.4.2 ECG/RESP........................................ ............................... .................................................21

2.4.3 NIBP ........................................................ .........................................................................22

2.4.4 SpO2........................... ............................... ........................................................................23

2.4.5 TEMP................................................................................................................................23

2.4.6 IBP....................................................................................................................................23

2.4.7 CO.....................................................................................................................................24

2.4.8 CO2............................ ............................... ........................................................................24

2.4.9 AG..................................... ............................... .................................................................24

CHAPTER 3. PRODUCT SPECIFICATIONS................................................... ............................27

3.1. SAFETY CLASSIFICATIONS........................................................................................................27

3.2. ENVIRONMENTAL SPECIFICATIONS ..........................................................................................27

3.3. POWER SOURCE SPECIFICATIONS ..........................................................................................28

3.4. HARDWARE SPECIFICATIONS ...................................................................................................29

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3.5. WIRELESS NETWORK ................................................................................................................30

3.6. DATA STORAGE .........................................................................................................................30

3.7. SIGNAL OUTPUT SPECIFICATIONS ...........................................................................................30

3.8. ECG SPECIFICATIONS..............................................................................................................31

3.9. RESP SPECIFICATIONS............................................................................................................36

3.10. SPO

SPECIFICATIONS .........................................................................................................36

2

3.11. NIBP SPECIFICATIONS .........................................................................................................38

3.12. TEMP SPECIFICATIONS .......................................................................................................39

3.13. IBP SPECIFICATIONS ............................................................................................................39

3.14. CO SPECIFICATIONS ............................................................................................................40

3.15. CO

SPECIFICATIONS...........................................................................................................40

2

3.16. AG SPECIFICATIONS ............................................................................................................43

CHAPTER 4 DISASSEMBLING/ASSEMBLING & TROUBLESHOOTING...............................45

4.1 DPM5 DISASSEMBLING/ASSEMBLING.....................................................................................45

4.1.2 DPM5 Display (TFT Display) Assembly ........................................................................46

4.1.3 DPM5 Support Assembly (Lithiu m Battery) (920 1-30-35944)......................................47

4.1.4 Front Cover Assembly.........................................................................................................48

4.1.5 Back Cover Assembly..........................................................................................................49

4.1.6 Microstream CO2 Assembly................................................................................................50

4.2 TROUBLESHOOTING ..................................................................................................................51

4.2.1 Black Screen, Startup Failure........... ..................................................................................51

4.2.2 White Screen & Other Abnormal Screen.........................................................................52

4.2.3 Encoder Faults..................................................................... .................................................52

4.2.4 No Audio Alarm................................................. ............................................................. .......52

4.2.5 Printing Failure............................. ............................... ..........................................................52

4.2.6 Abnormal Paper Drive.........................................................................................................52

CHAPTER 5 TEST AND MATERIAL LIST.....................................................................................53

5.1 TEST PROCEDURE ....................................................................................................................53

5.1.1 Connection and Checking...................................................................................................53

5.1.2 Functions of Buttons............................................................................................................53

5.1.3 ECG/RESP............................................................................................................................53

5.1.4 Temperature .......................................................................................... ................................53

5.1.5 NIBP........................................................................................................................................54

5.1.6 SpO2............................ ............................... .............................................................................54

5.1.7 IBP...........................................................................................................................................54

5.1.8 CO......................................... ............................................................. .....................................55

5.1.9 CO2............................ ............................... ...............................................................................55

5.1.10 Water trap............................................................................................................................55

5.1.11 Recorder................................................................................................. ..............................56

5.1.12 Power Supply............................. ............................................................. ............................56

5.1.13 Clock .................................................................................... .................................................56

5.1.14 System Test................................................................... ......................................................57

5.2 NIBP CALIBRATION...................................................................................................................57

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Service Manual (V 3.0)

5.3 IBP CALIBRATE .........................................................................................................................57

5.4 CO2 CHECK..................................................................................................................................60

5.5 AG CALIBRATE ............................................................................................................................61

5.6 DPM5 MATE RIAL LIST..............................................................................................................63

CHAPTER 6 MAINTENANCE AND CLEANING............................. .................................................65

6.1 MAINTENANCE .................................................................................................................................65

6.1.1Checking Before Using.........................................................................................................65

6.1.2 Regular Checking.................................................................................................................65

6.2 CLEANING..................................................................................................................................65

6.3 CLEANING REAGENT ................................................................................................................65

6.4 STERILIZATION ..........................................................................................................................66

6.5 DISINFECTION ...........................................................................................................................66

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Service Manual (V 3.0)

FOR YOUR NOTES

4

Chapter 1 About the Product

Chapter 1 About the Product

1.1 Introduction

The DPM5 Patient Monitor, a portable and accessible patient monitor, is supplied by

rechargeable batteries or external AC power, which applies to adults, pediatric and neonates.

You can select different configurations as required. Besides, the

the central monitoring system whereby a monitoring network will be formed. Parameters that

the DPM5 can monitor include: ECG, RESP, SpO

and CO

freezing and recording, is a compact and lightweight patient monitor. Its color TFT LCD is able

to show patient parameters and 8 waveforms clearly. The compact control panel and knob

control, and the easy-to-use menu system enable you to freeze, record, or perform other

operations conveniently.

The DPM5 Patient Monitor measures patient’s ECG, NIBP, SpO

CO

and pressure transducer. During the measurement, the patient monitor does not get energy or

any substance from the human body, and does not release any substance to the human body.

However, it releases sine wave signals to the patient when measuring the respiration rate. The

patient monitor converts the measured physiological signals to the digital signals, waveforms

and values, and then displays them on the screen. You can control the patient monitor through

the control panel. For example, you can set different alarm limits for different patients. Thus,

when the patient monitor detects any physiological parameter exceeding the preset alarm limit,

it will enable the audio and visual alarm.

. It, integrating the functions of parameter measurement, waveform monitoring,

2

physiological signals through the ECG electrode, SpO2 sensor, cuff, temperature sensor

2

, NIBP, 2-channel TEMP, 2-channel IBP, CO

2

DPM5 can be connected with

, TEMP, RESP, IBP, CO and

2

1.2 Application

1.2.1 General

In the treatment processes, it is necessary to monitor important physiological information of

patients. Therefore, the patient monitor has been playing an outstanding role among medical

devices. The development of technology does not only help medical staff get the important

physiological information, but also simplifies the procedures and makes it more effective. For

patients in hospital, the basic and important physiological information is required, including

ECG, SpO

technology helping measure and get important physiological information of patients has made

the patient monitor more comprehensive in performance and better in quality. Today,

multi-parameter patient monitors are widely used.

, RESP, IBP, CO, CO2, TEMP, etc. In recent years, the development of science and

2

1

Chapter 1 About the Product

1.2.2 Usage

Parameters that the DPM5 can monitor include: ECG, RESP, SpO2, NIBP, TEMP, IBP, CO

AGand CO

. DPM5 converts these physiological signals to digital signals, processes them and

2

displays them on the screen. You can set the alarm limit as required. When the monitored

parameter exceeds the preset alarm limit, the patient monitor will start the alarm function. In

addition, you can control the patient monitor through the control panel. Usually, patient

monitors are seen in some clinical areas in hospital, such as ICU, CCU, intensive care units for

heart disease patients, operating rooms, emergency departments and observation wards.

They can also be used in clinics. The DPM5 patient monitor should be run under the control of

clinical staff.

DPM5 patient monitor has the following functions:

ECG

Heart Rate (HR)

2-channel ECG waveform

Arrhythmia analysis and S-T analysis (optional)

Respiration Rate (RR) RESP

Respiration waveform

Pulse Oxygen Saturation(SpO

Plethysmogram

SpO

2

), Pulse Rate (PR) SpO2

2

NIBP Systolic pressure (NS), diastolic pressure (ND), mean pressure

(NM)

TEMP T1, T2, TD

IBP CH1: SYS, DIA

CH2: SYS, DIA

IBP waveform

CO Temperature of blood (TB)

Cardiac Output (CO)

End-tidal carbon dioxide (EtCO2)

CO

2

Inspired minimum CO

(InsCO2)

2

Airway Respiration Rate (AwRR)

AG

Inhaled and exhaled CO

2

(FiCO2, EtCO2)

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Chapter 1 About the Product

Inhaled and exhaled N2O (FiN2O, EtN2O)

Inhaled and exhaled O

(FiO2, EtO2)

2

Inhaled and exhaled anesthetic agent (FiAA, EtAA, where AA

refers to any of the following anesthetic agents.)

HAL (Halothane)

ISO (Isoflurane)

ENF (Enflurane)

SEV (Sevoflurane)

DES (desflurane)

Airway Respiration Rate (rpm: Respiration Per Minute): AwRR

Minimum Alveolar Concentration (MAC)

4 AG waveforms (CO

, N2O, O2, AA)

2

The DPM5 provides the functions of audio/visual alarm, trend graphic storage and output,

NIBP measurement, alarm event identification, large font screen, defibrillator synchronization,

oxyCRG recall, drug calculation, etc.

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Chapter 1 About the Product

FOR YOUR NOTES

4

Chapter 2 Principles

Chapter 2 Principles

2.1 General

The intended use of the DPM5 patient monitor is to monitor a fixed set of parameters including

ECG, RESP, SpO

of the following functional parts:

Parameter measurement;

Main control part;

Man-machine interface;

Power supply;

Other auxiliary functions;

These functional units are respectively detailed below.

, NIBP, TEMP, IBP, CO and CO2 (IBP, CO and CO2 are optional). It consists

2

Figure 2-1 Structure of the DPM5

2.1.1 Parameter Measurement

The parameter measurement and monitoring are the core functions of the patient monitor. The

parameter measurement part of the DPM5 patient monitor consists of the measurement probe,

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Chapter 2 Principles

parameter input socket assembly, NIBP assembly and the main control board.

This part converts the physiological signals to electric signals, processes the those signals and

conducts the calculation by the preset program or command delivered from the main control

board, and then sends the values, waveforms and alarm information (which will be displayed

by using the man-machine interface) to the main control board.

2.1.2 Main Control Part

In the DPM5 patient monitor, the main control part refers to the main control part of the main

control board. It drives the man-machine interface, manages the parameter measurement and

provides users with other special functions, such as storage, recall of waveforms and data.

(See Figure 2-1)

2.1.3 Man-Machine Interface

The man-machine interface of the DPM5 patient monitor includes the TFT display, recorder,

speaker, indicator, buttons and control knob.

The TFT display is the main output interface. It, with the high resolution, provides users with

abundant real-time and history data and waveforms as well as various information and alarm

information.

The recorder is a subsidiary of the display, which is used for the user to print data.

The speaker provides the auditory alarm function.

The indicator provides additional information about the power supply, batteries, alarms and so

on.

The buttons and control knob are the input interface, which are used for the user to input the

information and commands to the patient monitor.

2.1.4 Power Supply

The power supply part is an important part of the patient monitor. It includes the main power

PCB, backlight board, batteries and fan.

The main power PCB converts the external AC current respectively to the 5V DC and 12V DC

current, which are supplied for the whole system. For the TFT display, there is a special

requirement on the power supply, so a backlight board is used. The batteries supply power for

the system for a short time when there is no external AC current. The fan is used for the heat

sink of the system.

2.1.5 Other Auxiliary Functions

The DPM5 patient monitor also provides the network upgrade function for the service

engineers to upgrade the system software without disassembling the enclosure.

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Chapter 2 Principles

2.2 Hardware Description

The structure of the DPM5 patient monitor is shown in the following figure.

Figure 2-2 Functional structure of the DPM5

7

Chapter 2 Principles

The DPM5 PCB connection is shown in the following figure.

Figure 2-3 PCB connection

Basic functions and working principles of modules are described in the following sections.

2.2.1 Main Board

2.2.1.1 General

The main board is the heart of the patient monitor. It implements a series of tasks, including the

system control, system scheduling, system management, data processing, file management,

display processing, printing management, data storage, system diagnosis and alarm.

2.2.1.2 Principle diagram

Figure 2-4 Working principle of the main board

8

Chapter 2 Principles

2.2.1.3 Principle

The main board is connected with external ports, including the power input port, multi-way

serial port, TFT display interface, analog VGA interface, network port and analog output port.

Besides, on the main board is also a BDM interface reserved for the software debugging and

software downloading.

CPU System

CPU is the core part of the main board. It, connected with other peripheral modules

through the bus and I/O cable, implements the data communication, data processing,

logical control and other functions.

RTC

RTC provides the calendar information (such as second, minute, hour, day, month and

year). CPU can read and modify the calendar information from RTC.

Ethernet Controller

Ethernet Controller supports the IEEE802.3/IEEE802.3u LAN standard, and supports two

data transmission rate: 10Mbps and 100Mbps. CPU exchanges data with the Ethernet

through the Ethernet Controller.

Analog Output

The D/A converter converts the digital ECG/IBP signals sent from CPU to the analog

signals, which are provided for the external after low-pass filtered by the filter and

amplified by the amplifier.

FPGA and VRAM

VRAM stores the displayed data. CPU stores the displayed data to VRAM through FPGA.

FPGA gets data from VRAM, processes them, and then sends them to the relevant

graphic display device.

In addition, FPGA also extends multiple serial ports, which communicate with peripheral

modules. FPGA transfers the received data to CPU through the bus; CPU delivers data to

FPGA through the bus, and then the FPGA transfers those data to the peripheral

modules.

Watchdog

When powered on, watchdog provides reset signals for CPU, FPGA and Ethernet

Controller.

The patient monitor provides the watchdog timer output and voltage detection functions.

2.2.2 ECG/RESP/TEMP Module

2.2.2.1 General

This module provides the function of measuring three parameters: electrocardiograph (ECG),

respiration (RESP) and temperature (TEMP).

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Chapter 2 Principles

2.2.2.2 Principle diagram

Figure 2-5 Working principle of the ECG/RESP/TEMP module

2.2.2.3 Principle

This module collects the ECG, RESP and TEMP signals through the transducer, processes the

signals, and sends the data to the main board through the serial port.

ECG Signal Input Circuit

The input protection and filtering circuits receive the ECG signal from the transducer, and filter

the high-frequency interference signal to protect the circuit against the damage by defibrillator

high-voltage and ESD.

The right-leg drive circuit gets the 50/60Hz power common-mode signal from the lead cable,

and sends the negative feedback signal to the human body to reject the common-mode

interference signal on the lead cable, which helps the detection of the ECG signal.

The lead-off detecting circuit checks whether the ECG lead is off, and sends the information to

CPU.

ECG Signal Process Circuit

The difference amplifying circuit conducts the primary amplification of the ECG signal and

rejects the common-mode interference signal.

The low-pas filtering circuit filters the high-frequency interference signal beyond the frequency

band of the ECG signal.

The PACE signal refers to the ECG pace signal. It has significant interference to the ECG

signal detection. The PACE rejection circuit can rejects the PACE signal, which helps the ECG

signal detection.

The main amplifying/filtering circuit conducts the secondary amplification of the ECG signal,

filters the signal, and then sends the ECG signal to the A/D conversion part.

Pace Detect

This part detects the PACE signal from the ECG signal and sends it to CPU.

Temperature Detect Circuit

This circuit receives the signal from the temperature transducer, amplifies and filters it, and

then sends it to the A/D conversion part.

10

Chapter 2 Principles

Carrier Generate Circuit

The RESP measurement is based on the impedance method. While a man is breathing, the

action of the breast leads to changes of the thoracic impedance, which modulates the

amplitude of the high-frequency carrier signal. Finally, the modulated signal is sent to the

measurement circuit. The purpose of this module is generating the high-frequency carrier.

RESP Signal Input Circuit

This circuit couples the RESP signal to the detecting circuit.

RESP Signal Process Circuit

The pre-amplifying circuit conducts the primary amplification of the RESP signal and filters it.

The detecting circuit detects the RESP wave that has been modulated on the actuating signal.

The level shifting circuit removes the DC component from the RESP signal.

The main amplifying/filtering circuit conducts the secondary amplification of the RESP signal,

filters the signal, and then sends it to the A/D conversion part.

A/D

The A/D conversion part converts the analog signal to the digital signal, and sends the signal

to CPU for further processing.

CPU System

 Implementing the logical control of all parameter parts and A/D conversion parts;
 Implementing the data processing for all parameters;
 Implementing the communication with the main board.

Power & Signal isolate Circuit

 Isolating the external circuits to ensure the safety of human body;
 Supplying power for all circuits;
 Implementing the isolation communication between the CPU System and the main

board.

11