Page 401 - Understanding Automotive Electronics

2735 | CH 11 Page 388 Tuesday, March 10, 1998 1:30 PM

11 FUTURE AUTOMOTIVE ELECTRONIC SYSTEMS

Speech Synthesis

Speech synthesizers use One really exciting new display device, information provided by
phoneme synthesis, a synthesized speech, has great potential for future automotive electronic
method of imitating the instrumentation. Important safety or trip-related messages could be given
basic sounds used to audibly so the driver doesn’t have to look away from the road. In addition to its
build speech. Comput- normal function of generating visual display outputs, the computer generates
ers rely on an inventory an electrical waveform that is approximately the same as a human voice
of phonemes to build speaking the appropriate message. The voice quality of some types of speech
the words for various synthesis is often quite natural and similar to human speech.
automotive warning The speech synthesis considered here must be distinguished from
messages. production voice message systems that have already appeared in production
cars. In these latter systems only “canned,” or preplanned, messages have been
available. In the true speech synthesis system, relatively complex messages can
be generated in response to outputs from various electronic subsystems. For
example, the trip computer could give fuel status in relationship to the car’s
present position and known fueling stations (both of the latter being available
from the navigation system). By combining information from several
subsystems on board the car it is possible to inform the driver of trip status at
any preprogrammed level of detail.
There are several major categories of speech synthesis that have been studied
experimentally. Of these, phoneme synthesis is probably the most sophisticated.
A phoneme is a basic sound that is used to build speech. By having an inventory of
these sounds in computer memory and by having the capability to generate each
phoneme sound, virtually any word can be constructed by the computer in a
manner similar to the way the human voice does. Of course, the electrical signal
produced by the computer is converted to sound by a loudspeaker.
Synthesized speech is being used to automatically provide data over the
phone from computer-based systems and is available on some production cars.

MULTIPLEXING IN AUTOMOBILES
One of the high-cost items in building and servicing vehicles is the
electrical wiring. Wires of varying length and diameter form the interconnection
link between each electrical or electronic component in the vehicle. Virtually the
entire electrical wiring for a car is in the form of a complex, expensive cable
assembly called a harness. Building and installing the harness requires manual
assembly and is time consuming. The increased use of electrical and electronic
devices has significantly increased the number of wires in the harness.
Sensor Multiplexing
The use of microprocessors for computer engine control, instrumentation
computers, etc., offers the possibility of significantly reducing the complexity of
the harness. For example, consider the engine control system. In the present
configuration, each sensor and actuator has a separate wire connection to the

388 UNDERSTANDING AUTOMOTIVE ELECTRONICS