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7.8 General interface circuit for speech-recognition circuit

To keep the interface circuit from becoming too large and at the
same time to enhance the robustness and accuracy of the SRC, we
will again limit the interface to control 10 on/off switches. If you
need the full 40-word vocabulary, you can design the interface cir-
cuit by expanding the circuit ideas illustrated in this chapter. Using
just 10 on/off switches allows us to use four word spaces for each
target (command) word, as before. Each of the four word spaces
assigned to a target word will hold a slightly different enunciation of
the target word. With four different enunciations of each target
word, the SRC becomes more robust and word recognition accuracy
increases.
We choose the word spaces as before, so that the LSD of any four
target (command) word spaces is the same. An example will make
this programming scheme clear.

Suppose we are making a voice control for an electric wheelchair.
We decide to use the following list of command (target) words:

Team LRN
Chapter seven