LIFEPAK 20/20e Defibrillator/Monitor
Device Description
Functional Description
(continued)
A01 System Control
PCB
(continued)
■
Paddles ECG Pre-Amplifier
— The paddles ECG pre-amplifier performs
patient-isolation, low-pass bandwidth filtering, and ECG sampling by means
of an analog-to-digital conversion (ADC) for the ECG signal received via the
therapy paddles. Results from the ADC are fed into the digital signal
processor (DSP) for additional filtering. Electrostatic discharge (ESD) and
defibrillation protection are provided for these signals as they pass through
the A04 Therapy PCB. Change in patient impedance is also measured using
a 57.1 kHz carrier.
■
Digital Signal Processor (DSP)
— The DSP completes ECG digital signal
processing to a diagnostic quality bandwidth, acceptable for Shock Advisory
System, heart rate algorithm processing, and continuous ECG storage by
the CPU. In addition, the DSP provides the necessary audio processing for
voice prompts and tones, providing digital audio signals to the audio output
circuitry.
■
Audio Output
— The audio output circuitry provides digital-to-analog
conversion, filtering, and power analog drive circuitry for the audio tones and
voice prompts. Up to 2 W of amplification are provided to drive the
W02 Speaker located on the front case of the device.
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