HT81003/HT81R03
5
July 24, 2000
Preliminary
System oscillator
The EasyVoice
TM
has a built-in RC oscillator
which requires only one external resistor for nor-
mal applications. The oscillator frequency is typi-
cally 2MHz for an external resistor of 150k . The
requiredoscillatorfrequencymayvarywithdiffer-
ent sampling rates in the process of voice pro-
gramming. As a result, the value of the oscillator
resistor may be different with respect to different
items.
The oscillator is turned on when triggered by a
keyinput.Afterplaying,itisimmediatelyturned
off. Then the chip goes into the standby state.
Voice ROM
The voice ROM is originally designed to continu-
ously record the 3-sec voice data at about 5kHz
samplingrate.Ahighersamplingratewillgener-
ate voices of better playback quality, but will
shorten the total recording time. On the other
hand, a lower sampling rate will result in longer
recording time but sacrifice the voice quality.
The playback time can be significantly extended
by making use of coding efficiency, silence play-
ing, section repeating, section cascade, etc.
Section
Section is the basic element constituting the
contents of the voice ROM. During program-
ming, the customer s voice sources can be di-
vided into as many sections as required. A
sectioncanbecomposed ofavoiceoraninterval
of silence. However, the silent length is not
counted in the voice ROM. The total number of
sections included should be less than 256 due to
the space limitation of the function table ROM.
The total length of the included sections is lim-
ited by the voice ROM.
Asection, when triggered by a key input, can be
played once, repeatedly or cascaded with other
sections, depending on the key function table
instructions.
The following are examples of section division:
In addition, a section can be set as retriggerable
or non-retriggerable depending on code option.
Retriggerable
When the currently playing section is set as
retriggerable, it will stop immediately upon
receipt of other key inputs.
Non-retriggerable
When the currently playing section is selected
as non-retriggerable, it will go on playing until
the whole section is completed, whether or not
there is a key input in the process of playing.
For a key group, some sections can be set as
retriggerable and some as non-retriggerable.
When a retriggerable section of a key group is
playing, any key can be triggered to interrupt
its playing. If it is a non-retriggerable section
playing, any key interrupt is invalid.
Group
The EasyVoice
TM
plays groups according to the
key input. A group can be made up of one or
more sections. When a key is triggered, the cor-
responding group is played. For example, trig-
gering KEY2 plays group 2, and so on. The
same section is allowed to appear in different
groups. However, KEY1 can be made up of mul-
tiple groups when it is optioned as a sequential
key. Otherwise, each key is composed by one
group only.
Key function table
The voice ROM sections are played according to
the instructions of the key function table. The
function table contains group information and
.
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