Votrax SC-01

The SC-01 was a synthesis IC created by Votrax International, Inc. It was most famous for its use in the arcade games Q*bert, Gorf and Wizard of Wor. The output from an SC-01 was sampled to create the Chipspeech voice Bert Gotrax, for which it is becoming more famous for.

Physical description
"The SC-01 Speech Synthesizer comprises a 22 pin monolithic (single level or substrate) integrated circuit of CMOS (Complimentary Metal On Silicon) design. [...] The P and N areas of the substrate, made by ion implantation, create a push-pull (Class B) transistor amplification and digital signal processing network. High impedance, rapid signal processing, and minimal current drain result from this technology."

Electrical description
"The SC-01 Speech Synthesizer is a program-compatible with existing Votrax® phoneme synthesizers. It requires 70 bits of data per second for continuous speech production. The 6-bit phoneme codes are 5 volt compatible and are latched for data bus line applications. A phoneme-construction algorithm and filters, within the chip, create the synthesized audio output."

Phoneme description
Main article: Votrax SC-01/Phoneme table

The SC-01 has a set of 64 phonemes. The phonemes are called upon using 6-bit phoneme codes which each have a phoneme symbol to go along with it, which are what appears to be a modified form of Arpabet.

Revisions
The SC-01 underwent a single revision, dubbed the SC-01-A. Physically speaking, they are the same chip, but there was a change made to the ROM which improved quality of synthesis.

"The SC-01 and SC-01-A have been decapped and the internal roms read out (mid-2007). The difference between the SC-01 and SC-01-A: the 01-A had some of the parameters changed for a few phonemes, ostensibly to increase sound quality and to remove some DC bias from the output."

"— Jonathan Gevaryahu"

Uses
Both the Votrax SC-01 and SC-01-A were used in many products, below is a list of some of them.
 * Alien Voicebox I and II
 * Gorf
 * Heathkit HERO 01 (ET-18)
 * Heathkit HERO Jr. (RT-1)
 * Q*bert
 * Votrax Type 'N Talk
 * Wizard of Wor