57. The speech synthesizer of claim 56 wherein said circuit means includes means for producing an enabling signal until said predetermined input data is received, and control means connected between said input means and said first and second modulating means that is adapted to prevent both said first control signal from being transmitted to said first modulating means and said second control signal from being transmitted to said second modulating means upon the termination of said enabling signal.
57. The speech synthesizer of claim 56 wherein said circuit means includes means for producing an enabling signal until said predetermined input data is received, and control means connected between said input means and said first and second modulating means that is adapted to prevent both said first control signal from being transmitted to said first modulating means and said second control signal from being transmitted to said second modulating means upon the termination of said enabling signal. 58. The speech synthesizer of claim 57 wherein said control means includes a first electronic control device adapted to conduct said first control signal whenever said enabling signal is produced and a second electronic control device adapted to conduct said second control signal whenever said enabling signal is produced.