초록 ▼

In a noise reduction system including a compressor and an expander having a complementary frequency response characteristic to the frequency response characteristic of the compressor, the compressor includes a high frequency emphasis variable frequency filter and a low frequency emphasis variable ga

In a noise reduction system including a compressor and an expander having a complementary frequency response characteristic to the frequency response characteristic of the compressor, the compressor includes a high frequency emphasis variable frequency filter and a low frequency emphasis variable gain filter which are connected in a series circuit between input and output terminals and which respectively vary their parameters in response to the respective high and low frequency components of the compressor output. The expander includes a high frequency de-emphasis variable frequency filter and a low frequency de-emphasis variable gain filter which are connected in a series circuit between input and output terminals and which respectively vary their parameters in response to the respective high and low frequency components of the expander input.

대표청구항 ▼

A noise reduction system having a compressor and an expander having a complementary frequency response characteristic to the frequency response characteristic of the compressor, said compressor comprising: first input and output terminals, means connected to the first output terminal for generating

A noise reduction system having a compressor and an expander having a complementary frequency response characteristic to the frequency response characteristic of the compressor, said compressor comprising: first input and output terminals, means connected to the first output terminal for generating a first control signal representing a high frequency component of a signal applied to said first output terminal, means connected to said first output terminal for generating a second control signal representing a low frequency component of said signal at said first output terminal, a high frequency emphasis variable frequency filter circuit of which the cutoff frequency is variable as a function of said first control signal, and a low frequency emphasis variable gain filter circuit of which the amount of emphasis is variable inversely as a function of said second control signal, said filter circuits being connected in a series circuit between said first input and output terminals, and said expander comprising; a second input terminal adapted for connection to said first output terminal, a second output terminal, means connected to said second input terminal for generating a third control signal representing a high frequency component of the signal at said second input terminal, means connected to said second input terminal for generating a fourth control signal representing a low frequency component of said signal at said second input terminal, a low frequency de-emphasis variable gain filter circuit of which the amount of de-emphasis is variable inversely as a function of said fourth control signal, and a high frequency de-emphasis variable frequency filter circuit of which the cutoff frequency is variable as a function of said third control signal, said filter circuits being connected in a series circuit between said second input and output terminals.