| 摘要 |
<p>PROBLEM TO BE SOLVED: To maintain uniformity of a burglar-alarm effect and a subliminal effect and to prevent the effects from being deteriorated by mounting a storage medium that is recorded by a sound with only an inaudible sound wave range within an audible limit to another independent reproduction device than a sound device usually listened to by a user and outputting the record simultaneously with the output of the sound device. SOLUTION: A sound signal from an in-shop broadcast equipment BC such as a wired broadcast or a satellite broadcast receiver is given to a low-pass filter circuit LF, where frequencies over 13-6 kHz are cut off. A sound signal in a speech outputted from a newly installed sound device such as a storage medium reproduction device (any device such as an externally connected device or a built-in internal unit configuring part of the circuit of the device BC) and converted into a signal in an ultrasonic range is given to a high-pass filter HF, where frequencies lower than 18-20 kHz are cut off. A mixer circuit MX mixes the two kinds of the sounds and the mixed signal is amplified by an amplifier AN and sounded from an external speaker SP.</p> |
