PAVAS – Audible sounds

PAVAS uses a variety of audible tones to convey information to the driver. It uses a speaker output and a dedicated speaker which is usually placed in the driver's helmet. The speaker size is arbitrary and the most used type is 22 to 25 mm with and impedance of 8 ohms. Using a separate speaker means that the driver's intercom is not interfered with. The speaker volume is programmable so the level can be set to the driver's preference. A separate volume level is programmed for the Alert speed level since this is often exceed with accompanying high noise levels.

The tone patterns are designed to be easily recognized so that interpretation is rapid. The use of tones means that the driver's vision is not diverted to assimilate speed information. The tone range is 300 to 3300 Hz which is well within the normal human hearing range. The upper limit is set by the frequency range of this class of speaker.

When in Alarm Speed Monitor, the tones are broken into three groups. If the vehicle is below a low speed limit, then no tone is sounded. Once the low speed limit is exceeded a pulsating tone is generated. The rate, duration and frequency increase as the speed increases. The net event is to sound an increased urgency as the speed increases.

The next level encountered is the Alert level. To distinguish this speed a warble in sounded. This is an alternating tone that varies from 1000 to 1800 Hz and sounds similar to an emergency vehicle. The purpose of this tone is to warn the driver that the vehicle is approaching the Alarm speed limit. Selection of this speed is arbitrary and, as a guideline, can be set to allow for the driver's reaction time before the vehicle reaches the Alarm speed.

The Alarm speed is set near the maximum speed for the for the event. The tone used is constant at 3300 Hz. The tone volume is set specifically for this alarm.

TSD and Regularity modes use Alert and Alarm tones to warn and indicate Alert and Alarm speeds. In addition they have Null Guidance to guide the driver to the designated average speed. They also have a Low Speed alarm which is triggers if the vehicle speed below a minimum for the stage or lap. This Low Speed alarm is a constant tone of 300 Hz.

The beep tone consists of two tones, one is 1000 Hz and the second is 1300 Hz. The tones have a duration of 200 milliseconds and changes from the low to the high frequency. The net effect is quite distinctive. When PAVAS boots, a beep tone sequence is sounded. This provides a quick check of the audio system, speaker and connections. The beep is also used in the Regularity mode to signal that the Regularity switch has been pressed.

PAVAS also has a remote speaker 3.5 mm mono output socket. This is designed to used with an external speaker. In many cases, a USB/Bluetooth speaker with an AUX input can be used.