Assembly for preventing phase error

An assembly configured to prevent phase error includes an input unit, a filter unit, a slicer unit, a subtraction unit and an addition unit. The input unit provides an original audio signal. The filter unit selects one part of an original audio signal according to a preset bandwidth setting on the filter unit to form a first audio signal, and outputs said audio signal from a second output terminal. The slicer unit analyzes the amplitude magnitude according to a preset threshold amplitude to form a second audio signal. The subtraction unit subtracts the first audio signal from the original audio signal to form a third audio signal. The second audio signal and the third audio signal have the same phase retardation. The addition unit adds the second audio signal and the third audio signal to form a fourth audio signal.

The present invention relates to audio signal processing techniques, and more specifically, to an audio system configured to compensate for various errors appearing in audio signals.

BACKGROUND

As shown inFIG. 1, a conventional technique uses crossover filter1to analyze audio signal X. The crossover filter1filters the audio signal X into two different band waves which is X1and X2. A first wave X1is transmitted to a slicer2, and is output as filtered signal X3. A second wave X2is output from the crossover filter and is combined with the first wave X1via a summer3to generate an output signal (X2+X3). However, the crossover filter1can introduce a phase error. For example, a low-pass filter section of the crossover filter1can introduce a lagging phase shift with increasing frequency, while a high pass section of the crossover filter1can introduces a leading phase shift. There is also a phase error between the wave X1and the audio signal X because wave X1would be effected by slicer2as wave X1being outputted from slicer2(namely wave X3). Also, there are some overlapped waves produced because of different phase error occurring between waves X2and X3while wave X2is adding to wave X3. Thus, the audio signal X has distortion.

In view of this, the at least one non-limiting embodiment provides an assembly configured to prevent phase error to solve the lack of conventional techniques.

SUMMARY

Various non-limiting embodiments provide an assembly configured to prevent phase error to reach the purpose of preventing distortion by a filter unit, a slicer unit, a subtraction unit, and an addition unit.

The at least one embodiment provides an assembly configured to prevent phase error to reach the purpose of phase compensation through the multi-stage circuit to synchronize the phase retardation.

The at least one embodiment provides an assembly configured to prevent phase error is applied to compressor linear circuit or analog circuit phase retardation.

To reach above-mentioned purposes and others, the at least one non-limiting embodiment provides an assembly configured to prevent phase error comprising a filter unit, a slicer unit, a subtraction unit, and an addition unit. The input unit comprises a first input terminal and a first output terminal. The first input terminal is applied to receive an original audio signal. The filter unit comprises a second input terminal and a second output terminal. The second input terminal is connected to the first output terminal. There is a preset bandwidth setting on the filter unit. The filter unit selects one part of original audio signal according to the preset bandwidth to output a first audio signal from the second output terminal. The slicer unit comprises a third input terminal and a third output terminal. The third input terminal is connected to the second output terminal. There is a threshold amplitude setting on the slicer unit. The slicer unit forms a second audio signal by analyzing the first audio signal amplitude according to the threshold amplitude. The second audio signal is output from third output terminal. The subtraction unit comprises a fourth input terminal, fifth input terminal, and the fourth output terminal. The fourth input terminal is connected to the first input terminal, and the fifth input terminal is connected to the second output terminal respectively. The subtraction unit subtracts the first audio signal from the original signal to form a third audio signal which is outputted from the fourth output terminal. Both the third audio signal and the second audio signal have the same phase retardation. The addition unit comprises a sixth input terminal, seventh input terminal and fifth output terminal. The sixth input terminal is connected to the fourth output terminal, and the seventh input terminal is connected to the third output terminal. The addition unit adds the second audio signal and the third audio signal to form a fourth audio signal, and the fourth audio signal is outputted from the fifth output terminal. The fourth audio signal is equal to the original audio signal, and there is a phase error between them.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1is a conventional technique block diagram for preventing phase error assembly;

FIG. 2is a block diagram illustrating an assembly configured to prevent phase error according to a first non-limiting embodiment; and

FIG. 3depicts various waveforms generated by the assembly illustrated inFIG. 2.

DETAILED DESCRIPTION

Various non-limiting embodiments will be described with reference to the drawing figures where like numerals represent like elements throughout.

FIG. 2is a block diagram of an assembly10configured to prevent phase error according to a first non-limiting embodiment. The assembly10is configured to prevent the phase error can be implemented on phase compensation to reach the purpose of preventing distortion.

The assembly10comprises an input unit12, a filter unit14, a slicer unit16, a subtraction unit18, and an addition unit20. In at least one embodiment, the slicer unit16may be constructed, for example, as a high-pass filter or a clipper circuit.

The input unit12comprises a first input terminal122and a first output terminal124. The input unit12could be a conductive wire patterns, a terminal interface patterns, or others. The first input terminal122is capable of receiving an original audio signal (OAS). An example of the OAS waveform is further illustrated inFIG. 3. The illustration of the OAS is generated as a sine wave, for example, which includes positive half-wave and negative half-wave.

The filter unit14comprises a second input terminal142and a second output terminal144. The filter unit14can be constructed as a filter circuit comprising at least two of a resistive element (not shown), a capacitive element (not shown), and an inductive element (not shown). The second input terminal142is connected to the first output terminal124. There is a preset bandwidth in the filter unit14. By adjusting the resistance of the resistive element, the capacitance of the capacitor, and the inductance of the inductive element, to determine the total impedance, the charging time, and the discharging time, the filter unit14has a preset bandwidth.

In at least one embodiment, the filter unit14includes at least one of a low pass filter (not shown), a band pass filter (not shown), and a high pass filter (not shown) according to its design. For example, the low pass filter r is configured to pass a low frequency waveform, the high pass filter is configured to pass a high frequency waveform, and the band pass filter is configured to pass a medium frequency waveform when the waveform comprises a low frequency, medium frequency, and high frequency.

The filter unit14selects one part of the original audio signal (OAS) according to the preset bandwidth, and outputs a first audio signal (FAS) from the second output terminal144. InFIG. 3, the preset bandwidth of filter unit14selects to let the positive half-wave of the original audio signal OAS, namely the first audio signal FAS, passing through. Since it is possible to generate a phase change when the OAS is passing through the filter unit14, for ease of explanation and further consideration of the phase change, it is set that there is a phase delay of first audio signal FAS comparing to the original audio signal OAS. The phase delay can be, for example, a multiple of 180 degrees.

The slicer unit16, comprises a third input terminal162and third output terminal164. The third input terminal162is connected to the second output terminal144to receive the FAS. There is a threshold amplitude preset in the slicer unit16. For example, the FAS is limited to the threshold amplitude to avoid abnormal voltage (generally, the abnormal voltage has a higher amplitude) when the FAS amplitude is greater or equal to the threshold amplitude. The slicer unit16determines the outputting amplitude intensity of the FAS according to the threshold amplitude, forms a second audio signal (SAS). The third output terminal164outputs the SAS. InFIG. 3, the output wave of slicer unit16is a positive half-wave as well as the filter unit14. However, considering aforesaid phase change situation, it is set that there is a phase error of the SAS with respect to the FAS. For example, a phase error being a multiple of 180 degrees, for example, can be introduced.

The subtraction unit18comprises a fourth input terminal182, a fifth input terminal184, and a fourth output terminal186. The fourth input terminal182is connected to the first output terminal124, and the fifth input terminal184is connected to the second output terminal144. The subtraction unit18subtracts the FAS from the OAS to form a third audio signal (TAS). Considering the aforesaid phase change situation, it is set that there is a delay of the third audio signal TAS with respect to the second audio signal TAS. The phase delay can be, for example, a multiple of 180 degrees. There is something noticeable that the FAS may be reversed and changed to negative half-wave in the slicer unit16, and further be added to the OAS, so that it may accomplish the feature of subtracting the FAS from the OAS. The TAS is output from the fourth output terminal186.

The addition unit20comprises a sixth input terminal202, a seventh input terminal204, and a fifth output terminal206. The sixth input terminal202is connected to the fourth output terminal186, and the seventh output terminal204is connected to the third output terminal164. The addition unit20adds the SAS and the TAS to form a fourth audio signal (FAS'). There is something noticeable that both the SAS and the TAS have the same phase shift, and the positive half-wave of the SAS is the same as the negative half-wave of the TAS. Therefore, during the adding process, the positive half-wave and the negative half-wave wipe one another out (i.e., cancel out each other) and then restore to the OAS, namely the fourth audio signal FAS'. The fifth output terminal206outputs the FAS' where the FAS' is equal to the OAS. In at least one embodiment there is a phase shift between the FAS' and the OAS. The phase shift between can be about 90-degrees, for example.

The subtraction unit18and the addition unit20include of an operational amplifier (not shown) and at least one of a resistive element (not shown), a capacitive element (not shown), and inductance element (not shown), respectively.

In at least one embodiment, the number of the filter unit14and the slicer unit16is just an example. In other embodiment, the number of the filter unit14and the slicer unit16could be plural.