Datasheet

Thursday, 17 July 2003 MiniProject: Design Aspects Colin K McCord
EEE512J2 – Electronic Product Design Page 14 Chapter 3: Feasibility / Initial Design Approach
visually displays the ECG. 7-segment displays display the beats per minute of the ECG, and a buzzer is
used to beep for each heart beat.
Differential
Amplifier
(ECG Amp)
Microboard
Surface
Electrodes
Oscilloscope
Buzzer
Figure 3.2c. Concept design 3, using a CRT and/or a PC to display ECG.
It was decide to developed concept 3, because it offered more features than 1&2, with only a small increase
in product cost. Allow it maybe useful to have a volume control on the beeper, using a buzzer this is difficult
to achieve as buzzers are either ON or OFF (some buzzers may drop in volume, if there input voltage is
decreased, but this is not ideal), hence the idea from concept 2 (audio amplifier with speaker) is still an
option because a volume control is easy to achieved (vary audio amplifier gain).
3.3. Initial Product Design Specification
ECG Display: Non fade with hold facility. Screen width – 50mm. Moving trace speed – 25 mm/sec
Anti-glare treated screen for high contrast.
Heart Rate Display: 3 digit 7-segment numeric readout LED displays 10 seconds average rate, updated
every 4 seconds. 30-240 bpm.
ECG Signal: 3 lead cable with AAMI standard 6-pin connector. Electrically isolated and fully
protected from overload.
QRS Bleeper: 0-240 bpm with rear panel volume adjustment.
Surgical Diathermy: A highly effective diathermy filter will be fitted as standard. Permits continuous
monitoring during electro-surgery.
Delayed Output: Operation of HOLD control stores the 3.3 seconds of ECG waveform on screen for
write-out to recorder from delayed output jack after release of HOLD.
Real-time Output: Allows real-time recording of ECG from real-time output jack at a fixed gain of
1V/mW. Buffered output for driving long, high capacitance cable.