Medical Alarm Analyzer tests medical equipment alarm signals for compliance with IEC 60601-1-8 and IEC 60601-2-24 requirements using audio WAV file recordings of the alarm signal.
This executable, plug-and-play application will work with WAV file recordings generated from any recording device. It conducts analysis of Low, Medium and High Priority Alarms for the following characteristics:
- Pulse shape and timing
- Sound pressure level
- Clipping
- Frequency
- Melodic sequence
Medical Alarm Analyzer includes several compliance modes, enabling you to test each of the following criteria:
- IEC 60601-1-8, Amendment 1, Tables 3 & 4
- IEC 60601-1-8, Amendment 2, Tables 3 & 4
- IEC 60601-1-8, Amendment 2, Annex G
- IEC60601-2-24
Overview
Medical Alarm Analyzer is set up to process a WAV recording of each of the four signal priority levels (High, Medium, Low and Information). 
Loading a WAV file into each quickly generates an overall Pass/Fail result.
Detailed results are shown on subsequent tabs, allowing you to troubleshoot failing alarms.
Pulse Timing & Level Analysis
The IEC 60601 standards lay out timing criteria for each pulse of a medial alarm. These include rise time, duration, fall time, pulse spacing, pulse interval, and level in dBA.
Medical Alarm Analyzer automatically detects the pulses within an alarm signal. It analyzes the envelope to determine where each pulse starts and ends. A graphical display includes cursors marking the start and end of each pulse’s rise and fall.
The timing results also include a table showing the following measurements for each pulse:
- Rise Time (tr)
- Pulse Duration (td)
- Fall Time (tf)
- Pulse Space (ts)
- Pulse Interval (x)
- Pulse Level (dBA)
Detailed Pass / Fail results for each pulse are displayed in another table.
The standards also specify other timing and level requirements for the overall burst, including:
- Number of Pulses
- Pulse level range (within 10 dB)
- Burst Spacing range
- Relative burst spacing between High, Low and Medium Priority signals
- Overall level
- Relative levels of High, Low and Medium Priority signals
- Range of levels of High, Low and Medium Priority signals
Medical Alarma Analyzer tabulates and displays these results as well.
Frequency Analysis
The 60601 Standards outline a number of criteria related to frequency content of each pulse. The Frequency Analysis tab in MAA give you a quick and intuitive way to see the harmonic results for each pulse.
Medical Alarm Analyzer performs frequency domain analysis of each pulse to detect Harmonic Components. A graphical view includes adjustable cursors for the Harmonic Components in the spectrum. A set of Pass/Fail LEDs indicates whether each pulse meets all frequency based criteria.
Detailed Pass/Fail results are shown for each pulse, making it easy to identity sources of failure.
Clipping Detection
IEC 60601-8 section 6.3.3.2 (e) specifies criteria Medical Alarm Analyzer includes three separate methods of clipping detection: Histogram, Time Waveform (Hard Clipping), and Spectral Balance (Soft Clipping).
The Histogram method works by performing a statistical analysis of all the samples in the pulse, and determining if a significant number of samples have a normalized level that exceeds a certain threshold. If the threshold is exceeded, clipping may have occurred.
Time Waveform method attempts to identify hard clipping by analyzing the waveform and looking for places where high level samples are repeated. If a certain percentage of the waveform contains segments of repeated samples, the detector indicates potential hard clipping.
The Spectral Balance method of clipping detection uses frequency domain analysis to find potential sof-clipped signals that may be caused by analog distortion.
Please contact VIacoustics at info@viacoustics.com for more information and an online demonstration of this product.
