Speech synthesizer for the Apple II computer

A speech synthesizer was designed and programmed to be used in conjunction with an APPLE II computer. Speech was made possible with a Voice Synthesis Processor (VSP) integrated circuit from Texas Instruments. The circuit reduces the sound of a spoken word to a block of coded data using a technique called “linear predictive coding.” The sound of a word was generated by transferring the data to the VSP, which decodes the data and provides an analog speech output. The circuit was built on a card which plugs into any of the peripheral connector slots l through 7 inside the APPLE chassis. An 8-ohm speaker was used to reproduce the sound of spoken words, and connects to the card with a two-wire cable. Synthesized speech adds a new dimension to human-interactive computer programs. The intent of the project was to make it easy to incorporate speech into existing or new BASIC programs. The speech data is loaded into the top of RAM memory, out of the way of user programs. The assembly language program which controls the VSP is located in an EPROM on the speech card. All the user has to add to a BASIC program are two short subroutines that provide the transition to the assembly program.