Scrambler system

A scrambler system comprising:

• an input terminal applied with an input audio signal which is to be scrambled;
• a first oscillator for generating a first local oscillation signal;
• first frequency dividing means for obtaining a first frequency divided signal by frequency-dividing said first local oscillation signal by 1/N;
• first triangular wave signal generating means for converting said first frequency divided signal into a first triangular wave signal, said first triangular wave signal being supplied unmodified to said first oscillator and controlling an oscillation frequency thereof;
• first multiplying means for obtaining a frequency converted audio signal by multiplying said first local oscillation signal with said input audio signal;
• pilot signal generating means for generating from said first frequency divided signal a pilot signal having a single frequency;
• first adding means for obtaining a scrambled signal by adding said pilot signal and said frequency converted audio signal;
• transmitting means for transmitting the scrambled signal through a predetermined transmission path so that the pilot signal coexists with the frequency converted audio signal on the predetermined transmission path;
• receiving means for receiving the scrambled signal which is transmitted through the predetermined transmission path;
• first separating means supplied with the scrambled signal from said receiving means for separating the pilot signal from the scrambled signal;
• square wave signal generating means for generating from the output separated pilot signal of said first separating means a square wave signal having approximately the same waveform as said first frequency divided signal;
• second triangular wave signal generating means for generating from said square wave signal a second triangular wave signal;
• a second oscillator for generating a second local oscillation signal which is approximately the same as said first local oscillation signal;
• second frequency dividing means for obtaining a second frequency divided signal by frequency-dividing said second local oscillation signal by 1/N;
• phase comparing means for comparing phases of said second frequency divided signal and said square wave signal and for generating a phase error signal;
• second adding means for obtaining an added signal by adding said phase error signal and said second triangular wave signal, said added signal being supplied to said second oscillator and controlling an oscillation frequency thereof;
• second separating means supplied with the scrambled signal from said receiving means for separating the frequency converted audio signal from the scrambled signal;
• and
• second multiplying means for obtaining the original input audio signal by multiplying said second local oscillation signal with the output separated frequency modulated audio signal of said second separating means.