How is an ultrasonic signal detected by the sensor and subsequently processed by the SONAPHONE?

In the SONAPHONE system, the sensor and handheld device together form the digital measurement chain.

The sensor first detects the ultrasonic signal at the inspection point. Depending on the sensor being used, this is either airborne or structure-borne sound.

In simplified terms, the measurement process consists of the following steps:

1. Detect the ultrasonic signal
2. Convert and condition the signal within the sensor
3. Transfer measurement data to the SONAPHONE
4. Process and evaluate the data in the SONAPHONE
5. Display, make audible and, where required, store the signal

How is the signal detected within the sensor?

With the BS10 and BS30 airborne sound sensors, an ultrasonic microphone detects sound pressure fluctuations in the air.

The microphone converts these fluctuations into an electrical signal over a broad frequency range. This signal is already amplified and digitized within the sensor.

With the BS20 structure-borne sound and temperature sensor, the mechanical ultrasonic signal is guided to the ultrasonic transducer by a waveguide. The transducer converts the structure-borne vibrations into an electrical signal, which is then amplified and digitized within the sensor.

How are the data transferred to the SONAPHONE?

The sensor is connected to the SONAPHONE via the sensor cable.

The SONAPHONE:

• supplies power to the sensor,
• automatically receives the measurement data from the sensor during measurement.

The subsequent processing is therefore based on the measurement data provided by the sensor rather than an unprocessed analogue sensor signal being carried throughout the complete measurement chain.

What happens in the SONAPHONE?

Further data processing and output take place in the SONAPHONE.

Depending on the app being used, the ultrasonic data can be used for:

• calculation and display of different level values,
• level records,
• calculation and display of the spectrogram,
• audible reproduction of the ultrasonic signal,
• application-specific assessments,
• recording and storage of measurement data,
• creation of inspection reports.

The SONAPHONE records broadband ultrasonic signals and can evaluate them simultaneously over a wide frequency range.

Why does part of the signal processing already take place in the sensor?

Signal conditioning and digitization within the sensor allow the measurement chain to be adapted to the respective sensor type.

Airborne and structure-borne sound sensors use different transducers and have different frequency responses and coupling conditions. The respective sensor is therefore an essential part of the overall measurement chain and influences the resulting measurement signal.

For comparable measurements, the same sensor type, accessories, and comparable measurement conditions should therefore be used.