Frequency expansion for synthesizer
AssigneePalm, Inc.
InventorIhle Marc
Life of this patent
Estimating the term…
Abstract
A method is provided for generating synthetic audio signals with a synthesizer by generating a synthesizer output signal with a low sampling rate of the synthesizer. Because of the low sampling rate, missing high-frequency components of the synthesizer output signal are generated by adding a high-frequency signal. An amplitude-modulated high-frequency signal is preferred, and the amplitude-modulated signal S and synthesizer output signal are converted to a higher sampling rate.
Claims17
A method for generating synthetic audio signals, the method comprising:
- providing a synthesizer for generating a synthesizer output signal with a low sampling rate of the synthesizer;
- generating missing high frequency components of the synthesizer output signal, due to the low sampling rate, by adding a high-frequency signal, wherein
- modulating an amplitude of the high-frequency signal;
- and
- converting the amplitude-modulated signal and the synthesizer output signal to a respectively higher sampling rate, wherein
- a common sampling rate conversion is used for conversation to the high sampling rate, with the synthesizer output signal being simultaneously converted to frequencies from 0 Hz up to a Nyquist frequency of the low sampling rate, and the amplitude-modulated signal is converted to frequencies from the Nyquist frequency of the low sampling rate up to the Nyquist frequency of the high sampling rate.
A system for generating synthetic audio signals, the comprising:
- a synthesizer for generating a synthesizer output signal with a low sampling rate of the synthesizer, wherein
- missing high frequency components of the synthesizer output signal are generated, due to the low sampling rate, by adding a high-frequency signal,
- an amplitude of the high-frequency signal is modulated, and
- the amplitude-modulated signal and the synthesizer output signal are converted to a respectively higher sampling rate, wherein
- a common sampling rate conversion is used for conversation to the high sampling rate, with the synthesizer output signal being simultaneously converted to frequencies from 0 Hz up to a Nyquist frequency of the low sampling rate, and the amplitude-modulated signal is converted to frequencies from the Nyquist frequency of the low sampling rate up to the Nyquist frequency of the high sampling rate.
A mobile device with an apparatus for generating synthetic audio signals, the apparatus comprising:
- a synthesizer for generating a synthesizer output signal with a low sampling rate of the synthesizer, and generating missing high frequency components of the synthesizer output signal, due to the low sampling rate, by adding a high-frequency signal;
- and
- a modulator to modulate an amplitude of the high-frequency signal to produce an amplitude-modulated signal, wherein
- a common sampling rate conversion is used for conversion to a high sampling rate, with the synthesizer output signal being simultaneously converted to frequencies from 0 Hz up to a Nyquist frequency of the low sampling rate, and the amplitude-modulated signal is converted to frequencies from the Nyquist frequency of the low sampling rate up to a Nyquist frequency of the high sampling rate.
Dependencies are inferred from the claim text.