Biomedical Instrumentation Amplifiers

1
Biomedical Instrumentation Amplifiers
Presented by- Md. Bashir Uddin Roll
1215502 Dept. of BME KUET, Khulna-9203
2
Biomedical Instrumentation

• Medical devices or instruments which are used to
  facilitate patient care, as well as biomedical
  research are known as medical instrument.
• Devices such as pacemakers, ultrasound machines,
  EKGs and blood pressure devices are just a few of
  the devices that are used in the biomedical
  field.
• A branch of biomedical engineering that deals
  with the knowledge of medical instruments and
  their application to the medical field is known
  as medical instrumentation.

3
Types of Medical Instrument

• Generally medical instruments can be grouped in
  two broad heads
• a) Diagnostic
• b) Therapeutic
• These are further subdivided into two or more sub
  groups
• Basic and Sophisticated,
• (ii) Mechanical, Electro-Mechanical Electronic

4
General Block Diagram of Medical Instrumentation
System
5
Basic Medical Instruments

• Measuring Instrument - Blood Pressure Instrument
• Recording Instrument ECG Machine
• Monitoring Instrument Heart Rate Monitoring
• Imaging Instrument MRI Machine
• Therapeutic Instrument ICU Ventilator
  Instrument

6
Recording Instrument

• ECG Machine

7
Monitoring Instrument

• It has capacity to monitor multi parameters of a
  patient
• Examples NIBP, IBP, Heart Rate,
• Body Temperature.
• ECG Tracing
• Normal and abnormal condition of patient
• Alarm facilities for monitoring parameters
• Alarm ensured physician and nurse attention

Bed side patient monitor
8
Imaging instrument
Medical Ultra sound Imaging Instrument
MRI Instrument
9
Therapeutic Instrument

• An ICU Ventilator instrument Is used for those
  patients who are unable to take breath normally

Picture of ICU Ventilator
10
Medical Instrumentation Amplifier

• An instrumentation (or instrumentational)
  amplifier is a type of differential amplifier
  that has been outfitted with input buffers,
• Which eliminate the need for input impedance
  matching
• Thus make the amplifier particularly suitable for
  use in measurement and test equipment.
• Amplifier used in medical field is called medical
  instrumentation amplifier.

11
Characteristics of medical instrumentation
amplifier

• A type of differential amplifier
• No need of impedance matching
• Outfitted with input buffers
• Very low DC offset
• Low drift
• Low noise
• Very high open-loop gain
• Very high common-mode rejection ratio
• Very high input impedances.

12
Circuit diagram of medical instrumentation
amplifier
An instrumentation amplifier
13
Preamplifier

• A preamplifier (preamp) is an electronic
  amplifier that prepares a small electrical signal
  for further amplification or processing.
• A preamplifier is often placed close to the
  sensor to reduce the effects of noise and
  interference.
• It is used to boost the signal strength to drive
  the cable to the main instrument without
  significantly degrading the signal-to-noise ratio
  (SNR).
• The noise performance of a preamplifier is
  critical.

14
Importance of preamplifiers

• Wide range of input sensitivities
• Covered virtually all signal sources
• Calibrated zero suppression to expanded desired
  portion of an input
• Rejects noise or unwanted signal components by
  using low pass filtering

15
Special features of preamplifiers

• Capacity neutralization
• Current injection
• Low leakage current
• Low dc drift suitable for intracellular
  measurements through high resistance fluid-filled
  electrodes

16
Classification of Preamplifiers

• Differential amplifiers
• Ac coupled amplifiers
• Carrier amplifiers
• DC amplifiers
• Chopper input dc amplifiers
• Chopper stabilized dc amplifiers
• DC bridge amplifiers
• Isolation Amplifiers

17
Applications of medical instrumentation amplifier

• Particularly suitable for use in measurement and
  test equipment.
• Instrumentation amplifiers are used where great
  accuracy and stability of the circuit both short-
  and long-term are required.

18
THANK YOU