Analog signal transfer system, variable compressor, and variable expander
AssigneeKabushiki Kaisha Audio-Technica
InventorsOsamu Yokoi, Yuki Abe
Life of this patent
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Abstract
An analog signal transfer system includes a transmission apparatus including a variable compressor that variably compresses input signals exponentially according to the amplitudes of the input signals; and a reception apparatus including a variable expander that variably expands the compressed signals exponentially according to the amplitudes of the compressed signals.
Claims10
An analog signal transfer system comprising:
- a transmission apparatus including a variable compressor that continuously and variably compresses input signals exponentially according to amplitudes of the input signals and generates compressed signals, wherein
- an output y of the variable compressor is represented according to a formula,
- y =x−B·exp(Ay)+C, and
- the compression ratio, CR, of the variable compressor is represented according to a formula,
- CR =1/(1+AB·exp(Ay));
- and
- a reception apparatus including a variable expander that continuously and variably expands the compressed signals exponentially according to amplitudes of the compressed signals and generates expanded signals, wherein
- an output y′ of the variable expander is represented according to a formula,
- y′=x′+B·exp(Ax′)−C, and
- the expansion ratio, ER, of the variable expander is represented according to a formula,
- ER =1+AB·exp(Ax′);
- wherein x is the input of the variable compressor, x′ is the input of the variable expander, and A, B, and C are any constant values.
A variable compressor that continuously and variably compresses input signals exponentially according to the amplitudes of the input signals and generates compressed signals, wherein
- an output y of the variable compressor is represented according to a formula,
- y =x −B·exp(Ay) +C, and
- the compression ratio, CR, of the variable compressor is represented according to a formula,
- CR =1/(1+AB·exp(Ay));
- wherein x is the input of the variable compressor, and A, B, and C are any constant values, the variable compressor comprising:
- a voltage control amplifier that amplifies the input signals according to a control voltage and outputs the amplified signals;
- an RMS detector that calculates root mean square of the outputted signals to obtain effective values of the outputted signals;
- and
- an EXP function circuit that converts the effective values of the outputted signals from the RMS detector into values of an exponential function and provides the converted values as the control voltage for the voltage control amplifier.
A variable expander that continuously and variably expands compressed signals exponentially according to the amplitudes of the compressed signals and generates expanded signals, wherein
- an output y′ of the variable expander is represented according to a formula,
- y′=x′+B·exp(Ax′)−C, and
- the expansion ratio, ER, of the variable expander is represented according to a formula,
- ER=1+AB·exp(Ax′);
- wherein x′ is the input of the variable expander, and A, B, and C are any constant values, the variable expander comprising:
- a voltage control amplifier that amplifies the compressed signals according to a control voltage and outputs the amplified signals;
- an RMS detector that calculates root mean square of the compressed signals to obtain effective values of the outputted signals;
- and
- an EXP function circuit that converts the effective values of the outputted signals from the RMS detector into values of an exponential function and provides the converted values as the control voltage for the voltage control amplifier.
Dependencies are inferred from the claim text.