In 1976 Texas Instruments (TI) wanted to design a device that would pronounce a word to be spelt out on a keyboard as a way to teach spelling. It needed to be inexpensive, so it needed to store as many words as possible in about 256 kbits of memory. It also needed to be portable, so the size and power consumption was also very important. By 1978 TI had managed pack the apparent performance of a several-thousand- dollar computer into the $50 device that we all know as the Speak & Spell thanks to the TMS0280 speech synthesis IC. TI already had the TMS1000 microcontroller that we looked at in the previous installment but is wasn’t powerful enough to do speech synthesis on its own. For that TI turned to their team that included Larry Brantingham, Paul Breedlove, Richard Wiggins and Gene Frantz. After a lot of research, they determined that consumers associated a dull monotone voice with computer generated speech which worked in their favour to greatly simplify the synthesis requirements. The result was the TMS0280 which used linear predictive coding to generate speech at a 10-kHz sample rate from audio data encoded at 1200 bits per second.
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