Mobile manual recording with real-time spectrogram observation

Connecting UltraSoundGate 116/112 to a laptop computer (e.g. a small SONY Vaio PCG-C1 series device or a JVC MP-XP7210/3210) creates a very light-weight (less than 1.4 kg) and compact recording companion. By mounting a carrying belt, your hands are free for holding the USG microphone, operating the computer or other activities. In this way, walking while looking at the real-time spectrogram display will be no problem. Once the Avisoft-RECORDER software is running, recording sessions can be started and stopped by pressing the UltraSoundGate trigger button. The acoustic real-time monitor acts like a common bat-detector for perceiving ultrasound signals. This would allow you to close the laptop because the keyboard and the sceen is not required (an overload indicator helps to prevent clipping in this operating mode). The unique real-time spectrogram display provides more precise information on the incoming sounds. A high-resolution real-time spectrogram mode is also available in Avisoft-SASLab Pro. A pre-trigger mechanism allows you to catch sounds arriving before pressing the trigger button. In some cases the automatic recording mode as described below may be useful. Text comments can be fed both into a LOG file and the created .wav files for documentary purposes. When the analysis software Avisoft-SASLab Pro is installed on the same laptop, subsequent in-depth analysis can be carried out immediately.

Stationary automatic field recording

The automatic (sound-activated) recording mode of the Avisoft-RECORDER software can be used for long-term observations. For quick setup, amplitude thresholds and sensitive frequency ranges can be adjusted graphically by mouse. Selectable pre-trigger and hold time parameters support optimal settings for various signal types. An entropy parameter threshold allows to exclude unwanted loud broad-band signals (e.g. insect noise, wind or rain drops) from triggering. A longer cable (up to about 20 m) may be switched between the microphone module and the UltraSoundGate. The acquired sound files are supplied with a high-resolution time-stamp allowing precise re-construction of temporal structures over longer periods of time. The Avisoft-SASLab Pro analysis software is prepared for easy browsing through the various files. A larger lead-acid battery connected to a laptop computer enables long-term recording for whole nights. By combining an economical laptop (e.g. SONY Vaio PCG-C1VE) with a large car battery, several days of unattended recording would be possible. Solar or wind energy systems may further extend the operating time. Additionally, a timer may be used to switch off the computer during daytime (in order to save battery power in bat monitoring applications). The recording software is capable of re-starting without user-interaction after power-on.

Laboratory recording

For laboratory recording the same principles are valid as described above, except that power supply would not be a problem. Some typical applications of the multichannel device USG416 are: * simultaneous monitoring/recording of several (acoustically isolated) animals * synchronous recording of a single animal moving in 2 or 3-dimensional space through several microphones. The arrival time differences at the different microphones can be used to calculate the current location of the vocalising animal.

External triggers and digital signals

The digital input of UltraSoundGate 116 and 416 can be used to trigger recording by external switches or other custom-built electronics with TTL output. In continuous recording mode, that input may be used to sample an external digital state. Subsequently, labels can be derived from the state or transitions of that digital channel. A light sensor connected to the digital input may also enable or inhibit the automatic recording mode.