Band-Split Digital Amplifier Switching for Tuner Noise Suppression
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Solution Overview
Problem
Conventional digital amplifiers face issues with reception malfunctions in tuners due to switching noise, leading to compromised high-band playback performance and reduced amplification efficiency, as they either deteriorate high-band output or decrease efficiency when setting switching frequencies.
Innovation Solution
A digital amplifier configuration that divides the input signal into bands, using a band division section, pulse width modulation, and a switching frequency control section to set switching frequencies for each band, allowing low frequencies for lower bands and high frequencies for higher bands, thereby minimizing noise influence on the tuner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switching frequency is set low to avoid influencing the receiving frequency, then reception malfunctions are prevented, but high-band playback performance deteriorates
Solution Approach 1:
The input signal is divided into multiple frequency bands (low band and high band) by the band division section. Each band is then processed by separate pulse width modulation sections with different switching frequencies. The low band uses a lower switching frequency to avoid tuner interference, while the high band uses a higher switching frequency to maintain playback performance.
Solution Approach 2:
Different switching frequencies are applied to different frequency bands of the input signal. The low band portion of the signal is modulated with a lower switching frequency that does not interfere with tuner reception, while the high band portion is modulated with a higher switching frequency that preserves audio quality.
2Reliability
If the switching frequency is set high to avoid influencing the receiving frequency, then reception malfunctions are prevented, but amplification efficiency decreases
Solution Approach 1:
The signal processing is segmented into different frequency bands, each with its own pulse width modulation section. The low band section operates at a lower switching frequency that maintains amplification efficiency, while the high band section operates at a higher frequency that avoids tuner interference.
Solution Approach 2:
Different switching frequencies are assigned to different portions of the frequency spectrum. The low frequency components are processed with efficient low-frequency switching, while the high frequency components use higher switching frequencies to prevent tuner interference.
3Device complexity
If a single switching frequency is used for the entire input signal band, then device complexity is reduced, but both high-band playback performance and amplification efficiency are compromised
Solution Approach 1:
The single signal processing chain is segmented into multiple parallel chains, each handling a specific frequency band. Each band has its own pulse width modulation section that can be optimized for that band's requirements, allowing high-band signals to use higher switching frequencies for better performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses switching noise impact on the tuner, maintaining high-band playback performance while improving amplification efficiency by optimizing switching frequencies for different signal bands.
Implementation Method 1
a pulse width modulation section that modulates the bands of the input signal divided in the band division section by a pulse width modulation scheme
Implementation Method 2
The amplification section 12 amplifies by switching operation the output signal subjected to pulse width modulation in the pulse width modulation section 11
Implementation Method 3
The LPF 13 removes the high frequencies produced by the switching operation, and outputs the output signal to a speaker 16
Data Source
AI summary
A digital amplifier amplifies an input signal from a tuner (107) which receives a broadcast wave of a set receiving frequency so as to suppress degradation of the high-band reproduction performance and lowering of the amplification efficiency. The digital amplifier includes: a band division unit (102) for dividing an input signal into a plurality of bands; a high-band pulse width modulation unit (103a) and a low-band pulse width modulation unit (103b) which modulate the input signal of the respective bands divided by the band division unit (102), by the pulse width modulation method; a switching frequency control unit (101) which obtains a receiving frequency in the tuner (107) and controls a switching frequency (fsa) in the high-band pulse width modulation unit (103a) and a switching frequency (fsb) in the low-band pulse width modulation unit (103b); and a high-band amplification unit (104a) and a low-band amplification unit (104b) which amplify the input signal which has been subjected to pulse width modulation by the high-band pulse width modulation unit (103a) and the low-band pulse width modulation unit (103b).