Improved peak detector

Abstract

A method of operating an encoder or a decoder. The method includes receiving an analysis signal of an audio signal and a filtered analysis signal, combining the filtered signal with the analysis signal to generate a combined signal using a max function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal. The method includes identifying a wide peak and a narrow peak of the combined signal.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to communications, and more specifically, to methods of supporting audio encoding and decoding and related encoders and decoders. BACKGROUND

[0002] In the field of audio encoding and decoding and in signal processing in general, it is of interest to find and identify the peak structure of a signal. For example, the distribution of the peak structure of a signal can be used to determine an encoding scheme to be used in the encoding / decoding, as various encoding schemes are more suitable for periodic peak distributions, while other encoding schemes are more suitable for sparse peak distributions. If the signal is a frequency spectrum, the peaks indicate the frequency and amplitude of the sinusoidal components of the signal to be analyzed.

[0003] Finding peaks in a discretely sampled signal can pose some problems, as potential peaks can lie between sample points of the signal. One way to solve this problem is to use an interpolation method that tries to estimate potential peaks using neighboring sample points [see 1, Eric Jacobsen, "On Location Interpolation of DFT Outputs"]. One way to implement this interpolation is to apply a low-pass filter to the signal. Peaks that are spread over several sample points can then contribute to an aggregated peak.

[0004] A simple example of such a filter can be a Hanning window of length 3 or a normalized Hanning window . Another example can be a triangular filter, e.g. .

[0005] A drawback of this filtering method is that peaks in the signal are reduced. This is shown in the article "A nonlinear lowpass filter that eliminates peak attenuation" by James McNames and Brahm Goldstein, published in 1988 in the conference proceedings of Acoustics, Speech, and Signal Processing. This article describes numerous and complex operations to eliminate peak attenuation and requires that the peaks of interest have a similar morphology, thus limiting the case to audio signals with peaks of a similar type and width. In the operations, a difference signal (the difference between the original signal and the filtered signal) is added back to the filtered signal with some masking applied, an estimated and applied gain, and further filtering and adding operations to obtain a signal in which the peaks are closer to the original signal than the filtered signal. SUMMARY

[0006] A disadvantage of the filtering approach is that narrow peaks can be more suppressed than wide peaks. This can penalize narrow peaks that can come from potential peaks close to the sampling points and thus have a smaller distribution. This can also be disadvantageous for functions that typically produce both narrow and wide peak structures, where the narrow peaks would be penalized.

[0007] An advantage that can be achieved using the inventive concept described herein is that both wide and narrow peaks of the original signal can be identified and the amplitude of the narrow peaks relative to the wide peaks can be determined.

[0008] According to a first aspect, there is provided a method of operating an encoder. The method comprises receiving an analysis signal and a filtered analysis signal of an audio signal, combining the filtered signal with the analysis signal to generate a combined signal using a maximum function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal. The method comprises identifying wide peaks and narrow peaks of the combined signal.

[0009] According to a second aspect, there is provided an encoder adapted to perform the method according to the first aspect.

[0010] According to a third aspect, there is provided an encoder comprising a processing circuitry and a memory coupled with the processing circuitry. The memory comprises instructions, which when executed by the processing circuitry, cause the encoder to perform operations comprising receiving an analysis signal and a filtered analysis signal of an audio signal, combining the filtered signal with the analysis signal to generate a combined signal using a maximum function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal, and identifying wide peaks and narrow peaks of the combined signal.

[0011] According to a fourth aspect, there is provided a computer program comprising program code to be executed by a processing circuitry of an encoder, whereby execution of the program code causes the encoder to perform operations according to the first aspect.

[0012] According to a fifth aspect, there is provided a computer program product comprising a non-transitory storage medium comprising program code to be executed by a processing circuitry of an encoder, whereby execution of the program code causes the encoder to perform operations according to the first aspect.

[0013] According to a sixth aspect, there is provided a method of operating a decoder. The method comprises receiving an analysis signal and a filtered analysis signal of an audio signal, combining the filtered signal with the analysis signal to generate a combined signal using a maximum function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal. The method comprises identifying wide peaks and narrow peaks of the combined signal.

[0014] According to a seventh aspect, there is provided a decoder adapted to perform the method according to the sixth aspect.

[0015] According to an eighth aspect, there is provided a decoder comprising a processing circuitry and a memory coupled with the processing circuitry. The memory comprises instructions, which when executed by the processing circuitry, cause the decoder to perform operations comprising receiving an analysis signal of an audio signal and a filtered analysis signal; combining the filtered signal with the analysis signal to generate a combined signal using a max function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal; and identifying wide peaks and narrow peaks of the combined signal.

[0016] According to a ninth aspect, there is provided a computer program comprising program code to be executed by a processing circuitry of a decoder, whereby execution of the program code causes the decoder to perform operations according to the sixth aspect.

[0017] According to a tenth aspect, there is provided a computer program product comprising a non-transitory storage medium comprising program code to be executed by a processing circuitry of a decoder, whereby execution of the program code causes the decoder to perform operations according to the sixth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate certain non-limiting embodiments of the inventive concepts. In the drawings:

[0019] Figure 1 is an illustration of how narrow peaks can be penalized by a low pass filtering function;

[0020] Figure 2 is a block diagram illustrating an operating environment in which the inventive concepts can operate according to some embodiments;

[0021] Figure 3 is a block diagram illustrating an encoder according to some embodiments of the inventive concepts;

[0022] Figure 4 is a block diagram illustrating a decoder according to some embodiments of the inventive concepts;

[0023] Figure 5 is a block diagram illustrating an embodiment of an improved peak detector according to some embodiments of the inventive concepts;

[0024] Figure 6 is a flow diagram illustrating the operation of an encoder or decoder according to some embodiments of the inventive concepts;

[0025] Figures 7 to 9 is a block diagram illustrating further embodiments of an improved peak detector according to some other embodiments of the inventive concept;

[0026] Figure 10 is a graph of a combined signal of an original signal and a filtered signal according to some embodiments of the inventive concept; and

[0027] Figures 11 to 13 is a flow chart illustrating the operation of an encoder or decoder according to some embodiments of the inventive concept. DETAILED DESCRIPTION

[0028] In the following, the inventive concept will be described more fully and in connection with a number of embodiments, of which an example is illustrated in the accompanying drawings. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. It should also be noted that these embodiments are not mutually exclusive. Components from one embodiment can be assumed to be present / used in another embodiment by default.

[0029] The following description presents various embodiments of the disclosed subject matter. The embodiments are presented to teach examples, and not to limit the scope of the disclosed subject matter. For example, certain details of the described embodiments can be modified, omitted, or extended without departing from the scope of the described subject matter.

[0030] Before the embodiments are described in more detail, Figure 2 An example of an operating environment for an encoder 200 as described herein that can be used to encode a bitstream is shown. The encoder 200 receives audio from a network 202 and / or a storage 204 and encodes the audio into a bitstream as described below and sends the encoded audio to a decoder 206 via a network 208. The storage 204 can be part of a repository of multi-channel audio signals (e.g., a repository of a store or streaming audio service, a separate storage component, a component of a mobile device, etc.). The decoder 206 can be part of a device 210 that has a media player 212. The device 210 can be a mobile device, a set-top device, a desktop computer, etc.

[0031] Figure 3is a block diagram illustrating elements of an encoder 200 configured to encode audio frames according to some embodiments of the inventive concepts. As shown, the encoder 200 can include a network interface circuit 305 (also referred to as a network interface) configured to provide communications with other devices / entities / functions / etc. The encoder 200 can also include a processor circuit 301 (also referred to as a processor) coupled to the network interface circuit 305 and a memory circuit 303 (also referred to as a memory) coupled to the processor circuit. The memory circuit 303 can include computer-readable program code that, when executed by the processor circuit 301, causes the processor circuit to perform operations according to embodiments disclosed herein.

[0032] According to other embodiments, the processor circuit 301 can be defined to include the memory such that a separate memory circuit is not needed. As discussed herein, operations of the encoder 200 can be performed by the processor 301 and / or the network interface 305. For example, the processor 301 can control the network interface 305 to send communications to the decoder 206 and / or receive communications from one or more other network nodes / entities / servers (e.g., other encoder nodes, library servers, etc.) through the network interface 305. Further, modules can be stored in the memory 303 and these modules can provide instructions such that, when the instructions of the modules are executed by the processor 301, the processor 301 performs the respective operations.

[0033] Figure 4 is a block diagram illustrating elements of a decoder 206 configured to decode audio frames according to some embodiments of the inventive concepts. As shown, the decoder 206 can include a network interface circuit 405 (also referred to as a network interface) configured to provide communications with other devices / entities / functions / etc. The decoder 206 can also include a processor circuit 401 (also referred to as a processor) coupled to the network interface circuit 405 and a memory circuit 403 (also referred to as a memory) coupled to the processor circuit. The memory circuit 403 can include computer-readable program code that, when executed by the processor circuit 401, causes the processor circuit to perform operations according to embodiments disclosed herein.

[0034] According to other embodiments, the processor circuit 401 can be defined to include the memory such that a separate memory circuit is not needed. As discussed herein, operations of the decoder 206 can be performed by the processor 401 and / or the network interface 405. For example, the processor circuit 401 can control the network interface circuit 405 to receive communications from the encoder 200. Further, modules can be stored in the memory 403 and these modules can provide instructions such that, when the instructions of the modules are executed by the processor circuit 401, the processor circuit 401 performs the respective operations.

[0035] As mentioned previously, a drawback of the low-pass filtering approach is that narrow peaks can be suppressed. This penalizes narrow peaks that can come from potential peaks that are close to the sampling points and thus have a smaller spread. This can also be disadvantageous for functions that typically produce both narrow and wide peak structures, where the narrow peaks would be penalized. In Figure 1 a graphical illustration of this problem can be found in Figure 1 where a narrow peak 100 of the original signal 102 is suppressed in the filtered signal 104, and a wide peak 106 is maintained at a higher amplitude in the filtered signal 104. In the original analysis signal 102, the narrow peak 100 can be found at index 150, and the wide peak 106 with a lower maximum can be found at index 200. Applying a low-pass filter of the form [0.25 0.5 0.25] results in a filtered analysis signal 104 where the narrow peak at index 150 has now been suppressed, and the maximum is now found at index 200. Note that the filtered analysis signal has been delay-compensated so that the peak index corresponds to the index of the unfiltered signal, i.e. the analysis signal 100.

[0036] In various embodiments of the inventive concept described below, a filtered version of the analysis signal is “combined” with the original signal using a maximum function or a maximum absolute value function. An advantage that can be obtained using various embodiments of the inventive concept is that both wide and narrow peaks of the original signal can be identified without penalizing the narrow peaks of the original signal. In Figure 10 a graphical illustration of the analysis signal, the filtered signal, and the combined signal can be found.

[0037] In the description described below, a peak of a signal is defined as a signal extremum of a signal of finite length. They can be positive or negative extrema. A peak can have a relatively large amplitude, i.e. larger than adjacent values. This comparison can be based on comparing the possible peak with a low-pass filtered version of the function. It can also be based on a relative distance to a reference level, e.g. a noise floor level of the signal or an average level of the signal.

[0038] With reference to Figure 5 and Figure 6 the operation of the encoder 200 and / or the decoder 206 (implemented using the structure of the block diagrams of Figure 3 and Figure 4 respectively) will now be discussed with reference to the flowcharts of Figure 6 According to some embodiments of the inventive concept. For example, the modules can be stored in the memory 303 of Figure 3 or the memory 403 of Figure 4 and the modules can provide instructions such that when the instructions of the modules are executed by the respective encoder / decoder processing circuitry 301, 401, the processing circuitry 301, 401 performs the individual operations of the flowcharts.

[0039] In the description described below, the inventive concept will be described using the encoder 200. The decoder 206 can also perform embodiments of the inventive concept described below.

[0040] In some embodiments of the inventive concept, the amplitude of narrow peaks 100 in the filtered signal can not be used for controlling some instances of the encoder 200 or the decoder 206. Thus, in block 601, the processing circuitry 301 receives an analysis signal of the audio signal and a filtered analysis signal, which is to be analyzed for peaks. The filtered signal can be received from the low-pass filter 500. In block 603, the processing circuitry 301 determines whether to use a combined signal for identifying wide peaks and narrow peaks of the analysis signal. The determination to use the combined signal is based on receiving an indicator in various embodiments. The indicator can be generated by an analysis block operating on, for example, the audio signal or the analysis signal, indicating whether narrow peaks of the analysis signal should be preserved or not.

[0041] For example, the input signal to be analyzed for peaks is denoted as wherein is the value of the analysis function at index The analysis signal may, for example, be a spectrum, wherein the peaks can represent sinusoidal components. The sinusoidal components can, for example, be used by an audio encoder operating in a sinusoidal coding paradigm. Another example is an error concealment unit in an audio decoder, which generates concealed audio in a sinusoidal synthesis paradigm. Another example is an inter-channel time difference (ITD) analysis of a parametric stereo encoder, wherein the ITD is identified by locating peaks of a cross-correlation spectrum.

[0042] The analysis signal is input to a filter, for example, the low-pass filter 500, to generate a filtered analysis signal . For example, the filter can be a FIR (finite impulse response) filter in the form of a normalized Hanning filter of length 3: Note that in various embodiments of the inventive concept, any low-pass filter structure can be used as long as it serves the purpose of averaging wide peaks distributed over several indices. It is beneficial to compensate any delay introduced by the filter so that the position of the peak indices of matches the position of the peak indices of the original signal . For , this means that the output result is shifted back in time by one sample, which is possible if the entire analysis signal is available at the time of analysis. This is typically the case for audio encoders operating on frames.

[0043] In many cases, the received filtered signal has a suppressed narrow peak 100 such that the amplitude of the wide peak 102 is higher than the suppressed narrow peak 100. In other words, the original signal has a narrow peak 100 with an amplitude higher than the amplitude of the wide peak 102. Thus, in some embodiments, receiving a filtered signal includes receiving a filtered signal that has a suppressed narrow peak 100 (see Figure 1 ) and a wide peak with an amplitude higher than the suppressed narrow peak. In other embodiments, the narrow peak 100 is suppressed but can still have a higher amplitude than the wide peak 102.

[0044] In block 605, in response to determining to use the combined signal to identify the wide peak and the narrow peak, the processing circuit 301 combines the filtered analysis signal 104 with the analysis signal 102 to generate a combined signal 800 (see Figure 10 ) using a max function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal.

[0045] In block 607, the processing circuit 301 runs a peak detection on the combined signal. In block 609, in response to determining not to use the combined signal, the processing circuit 301 runs a peak detection on the filtered analysis signal 104.

[0046] In some embodiments, the indicator can control a switch 506 that, in one position, connects the low pass filter 500 to the peak detector 504 and, in another position, connects the combined signal output from the max absolute amplitude combiner 502, where each point of the signal is selected depending on the maximum absolute value of the signal at that point. In some embodiments, the switch 506 is located before the peak detector 504, as shown in Figure 5 This enables both the filtered analysis signal and the combined signal to be analyzed to determine whether to use the combined signal. In other embodiments, the switch 506 is located between the low pass filter 500 and the peak detector 504, as shown in Figure 7 Figure 7 The embodiments shown can reduce computation, as the combined signal computation can not be computed in various embodiments when the combined signal is not used.

[0047] In various embodiments of the inventive concept, the original analysis signal and the low pass filtered analysis signal are combined using the maximum absolute value at each index i. The combined signal generated using the maximum absolute value at each index i is generated according to:

[0048]

[0049] where, is the analysis signal, and​ is the filtered signal.

[0050] When combining the original analysis signal and the filtered analysis signal, a weighting function can be used. Thus, generating the combined signal using the maximum absolute value at each index i is generated according to:

[0051]

[0052] wherein, is the analysis signal, is the filtered signal, and is the weight. In some embodiments can be in the range of [0.50 - 1].

[0053] In other embodiments of the inventive concept, only positive peaks are of interest. In this case, the absolute function can be omitted and the combination of the original signal and the filtered signal is used to generate a combined signal that only identifies positive peaks. Thus, generating the combined signal that only identifies positive peaks is generated according to:

[0054]

[0055] wherein, is the analysis signal, and is the filtered signal.

[0056] When combining the original analysis signal and the filtered analysis signal, a weighting function can be used. Thus, generating the combined signal that only identifies positive peaks is generated according to:

[0057]

[0058] wherein, is the analysis signal, is the filtered signal, and is the weight. In some embodiments can be in the range of [0.50 - 1].

[0059] In yet another embodiment, negative peaks are identified. In this case, the selection of elements of the combined signal uses the minimum value according to:

[0060]

[0061] wherein, is the analysis signal, and is the filtered signal.

[0062] Turning to Figure 8 and Figure 9In yet other embodiments, the original analysis signal is scaled by a factor prior to being combined with the filtered signal.

[0063]

[0064] wherein is the analysis signal, is the filtered signal, and is a normal number, wherein a suitable value can be the largest coefficient of the low-pass filter, e.g. In other embodiments, the value can generally match the largest amplification of the low-pass filter when fed with an impulse (e.g., a Dirac impulse with amplitude 1).

[0065] From a complexity point of view, it can also be advantageous to insert the original values only at a limited number of indices (e.g., at the positions of the maxima) before applying the filtering.

[0066]

[0067] wherein is the analysis signal, is the filtered signal, is a normal number, and is a set of indices of at least one extremum point or maximum of the original signal Then only the comparison and combination operations need to be performed for the indices in

[0068] The detected peaks are output from the peak detector 504 and other functions / components (not shown) of the encoder (or decoder) are used to run peak analysis on the resulting signal.

[0069] Various operations from the flowchart of Figure 6 may be optional for some embodiments of the communication device and related methods. With respect to the methods of example embodiments 1, 17, 18, 33, 34, 35, 51, 52, 68, and 69 (described below), for example, Figure 6 the operations of block 603 and block 609 of

[0070] Figure 11 The operations of the encoder 200 and / or decoder 206 (implemented using the structure of the block diagrams of Figure 3 and Figure 4 respectively) are now discussed with respect to the flowchart of Figure 11 For example, the modules can be stored in Figure 3 ​memory 303 or Figure 4 The modules can be stored in the memory 403 of the encoder / decoder 401 or 301 and the modules can provide instructions such that when the instructions of the modules are executed by the corresponding encoder / decoder processing circuitry 301, 401, the processing circuitry 301, 401 performs the individual operations of the flowchart.

[0071] Turning to Figure 11 In block 1101, the processing circuitry 301 or 401 receives an analysis signal of an audio signal and a filtered analysis signal, the analysis signal to be analyzed for peaks. The filtered signal can be received from the low pass filter 500.

[0072] In block 1103, the processing circuitry 301 or 401 shifts the filtered signal such that the peak index of the filtered signal matches the peak index of the analysis signal. In block 1105, the processing circuitry 401 or 301 combines the filtered signal with the analysis signal to generate a combined signal that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal. In various embodiments, the combined signal can include weighting the signals as described herein. In other embodiments, the combined signal can include scaling the analysis signal as described herein.

[0073] In block 1107, the processing circuitry 301 or 401 determines whether to use the combined signal to identify wide peaks and narrow peaks of the analysis signal of the audio signal. The determination of whether to use the combined signal can be based on receiving a combined signal indicator that indicates whether to use the combined signal. The combined signal indicator can control a switch 506 (see Figure 5 and Figure 7 ) that connects the low pass filter 500 to the peak detector 504 in one position and connects the combined signal output from the maximum absolute magnitude combiner 502 in another position. In some embodiments, the switch 506 is located before the peak detector 504 as shown in Figure 5 This enables both the filtered analysis signal and the combined signal to be analyzed to determine whether to use the combined signal. In other embodiments, the switch 506 is located between the low pass filter 500 and the peak detector 504 as shown in Figure 7 Figure 7 Embodiments shown in

[0074] In block 1109, in response to determining to use the combined signal to identify wide peaks and narrow peaks, the processing circuitry 301 or 401 identifies wide peaks and narrow peaks of the combined signal, where the wide peaks and narrow peaks are characterized by an index i and a magnitude.

[0075] ​In various other embodiments of the inventive concept, the combined signal is only used to analyze the peak values of the signal. Turning to Figure 13 In these different other embodiments, in block 1301, the processing circuitry 301 or 401 combines the filtered signal with the analysis signal only at the maximum value position of the analysis signal before the analysis signal is filtered. In block 1303, the processing circuitry 301 or 401 uses the combined signal only at the position of the maximum value. In block 1305, the processing circuitry 301 or 401 uses the filtered signal at all other positions.

[0076] Returning to Figure 11 In block 1111, in response to determining that the combined signal is not used to identify wide and narrow peaks, the processing circuitry 301 or 401 identifies wide and narrow peaks of the filtered analysis signal, where the wide and narrow peaks are characterized by an index i and an amplitude.

[0077] Various operations from the flowchart of Figure 11 may be optional for some embodiments of the encoder / decoder and related methods. With respect to the methods of example embodiments 1, 17, 18, 33, 34, 35, 51, 52, 68, and 69 (described below), for example, Figure 11 the operations of block 1103 and block 1111 of the flowchart of

[0078] Figure 12 Embodiments are shown in which the decision whether to use the combined signal is made before block 1103 (shifting the filtered signal) and block 1105 (combining the filtered signal). Thus, the processing circuitry 301 or 401, after receiving the filtered signal of the analysis signal, determines whether to use the combined signal to identify wide and narrow peaks in block 1201. In this embodiment, the computation and processor operations can be reduced because the shifting of the filtered signal and the combined signal computation are not needed in various embodiments when the combined signal is not used.

[0079] It can be seen that various embodiments of the inventive concept balance the narrow and wide peaks of the analysis signal by combining the filtered signal and the unfiltered signal (i.e., the original signal) to generate a combined signal, where the peak analysis is run on the merged signal.

[0080] Example embodiments are discussed below.

[0081] Embodiment 1. A method of operating an encoder, the method comprising:

[0082] receiving (601, 1101) a filtered signal of an analysis signal of an audio signal, the analysis signal to be analyzed for peak values;

[0083] combining (605, 1105) the filtered signal with the analysis signal to generate a combined signal using a max function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal; and

[0084] identifying (607, 1109) a wide peak and a narrow peak of the combined signal, wherein the wide peak and the narrow peak are characterized by an index i and an amplitude.

[0085] Embodiment 2. The method of embodiment 1, wherein combining (605, 1105) the filtered signal with the analysis signal comprises combining (605, 1105) the filtered signal with the analysis signal in response to determining to use the combined signal to identify the wide peak and the narrow peak (603, 1107, 1201).

[0086] Embodiment 3. The method of any one of embodiments 1-2, wherein receiving the filtered signal of the analysis signal comprises receiving a low pass filtered signal.

[0087] Embodiment 4. The method of any one of embodiments 1-3, further comprising determining to use the combined signal based on receiving an indicator.

[0088] Embodiment 5. The method of any one of embodiments 1-4, wherein receiving the filtered signal comprises receiving a filtered signal having a narrow peak that is suppressed and a wide peak that has an amplitude that is higher than the suppressed narrow peak.

[0089] Embodiment 6. The method of any one of embodiments 1-5, further comprising shifting (1105) the filtered signal such that a peak index of the filtered signal matches a peak index of the analysis signal.

[0090] Embodiment 7. The method of any one of embodiments 1-6, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0091] Embodiment 8. The method of embodiment 7, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0092]

[0093] wherein, is the analysis signal, and is the filtered signal.

[0094] Example 9. The method of any of Examples 1-6, wherein combining the filtered signal with the analysis signal to generate the combined signal using a maximum function comprises combining the filtered signal with the analysis signal to generate the combined signal using a weighted maximum absolute value at each index i.

[0095] Example 10. The method of Example 9, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0096]

[0097] wherein, is the analysis signal, is the filtered signal, and is a weight.

[0098] Example 11. The method of Example 10, wherein, is in the range of [0.50 - 1].

[0099] Example 12. The method of any of Examples 1-6, wherein combining the filtered signal with the analysis signal to generate the combined signal using an extremum function comprises combining the filtered signal with the scaled analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0100] Example 13. The method of Example 12, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0101]

[0102] wherein, is the analysis signal, is the filtered signal, and is a scaling factor.

[0103] Example 14. The method of Example 13, wherein combining the filtered signal with the scaled analysis signal to generate the combined signal using a maximum function comprises combining the filtered signal with the scaled analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0104] Example 15. The method of Example 14, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0105]

[0106] wherein, is an analysis signal, is a filtered signal, is a weight, and is a scaling factor.

[0107] Embodiment 16. The method of embodiment 15, wherein, is in the range of [0.50 - 1], and is based on a maximum amplification of a low pass filter generating the filtered signal

[0108] Embodiment 17. The method of any of embodiments 1 to 16, wherein combining the filtered signal comprises combining (1301) the filtered signal only at positions of a maximum value of the analysis signal before filtering the analysis signal

[0109] Embodiment 18. An encoder (200) adapted to perform according to any of embodiments 1 to 17.

[0110] Embodiment 19. An encoder (200) comprising:

[0111] processing circuitry (303); and

[0112] memory (305) coupled with the processing circuitry, wherein the memory includes instructions that, when executed by the processing circuitry, cause the communication device to perform operations comprising:

[0113] receiving (601, 1101) a filtered signal of an analysis signal of an audio signal, the analysis signal to be analyzed for a peak;

[0114] combining (605, 1105) the filtered signal with the analysis signal to generate a combined signal using a maximum function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal; and

[0115] identifying (607, 1109) a wide peak and a narrow peak of the combined signal, wherein the wide peak and the narrow peak are characterized by an index i and an amplitude.

[0116] Embodiment 20. The encoder (200) of embodiment 19, wherein combining (605, 1105) the filtered signal with the analysis signal comprises combining (605, 1105) the filtered signal with the analysis signal in response to determining (603, 1107, 1201) to use the combined signal to identify the wide peak and the narrow peak.

[0117] ​​Example 21. The encoder (200) of any of Examples 19-20, wherein receiving the filtered signal of the analysis signal comprises receiving a low pass filtered signal.

[0118] Example 22. The encoder (200) of any of Examples 19-21, further comprising determining to use a filter based on receiving a filter indicator.

[0119] Example 23. The encoder (200) of any of Examples 19-22, wherein receiving the filtered signal comprises receiving a filtered signal having suppressed narrow peaks and wide peaks having amplitudes that are higher than the suppressed narrow peaks.

[0120] Example 24. The encoder (200) of any of Examples 19-23, further comprising shifting (905) the filtered signal so that peak indices of the filtered signal match peak indices of the analysis signal.

[0121] Example 25. The encoder (200) of any of Examples 19-24, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0122] Example 26. The encoder (200) of Example 25, wherein generating the combined signal using the maximum absolute value at each index i is generated according to:

[0123]

[0124] wherein, is the analysis signal, and is the filtered signal.

[0125] Example 27. The encoder (200) of any of Examples 19-24, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0126] Example 28. The encoder (200) of Example 27, wherein generating the combined signal using the maximum absolute value at each index i is generated according to:

[0127]

[0128] wherein, is the analysis signal, is the filtered signal, and is a weight.

[0129] Embodiment 29. The encoder (200) of embodiment 28, wherein, is in the range of [0.50 - 1].

[0130] Embodiment 30. The encoder (200) of any of embodiments 19-24, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the scaled analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0131] Embodiment 31. The encoder (200) of embodiment 30, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0132]

[0133] wherein, is the analysis signal, is the filtered signal, and is a scaling factor.

[0134] Embodiment 32. The encoder (200) of embodiment 31, wherein combining the filtered signal with the scaled analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the scaled analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0135] Embodiment 33. The encoder (200) of embodiment 32, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0136]

[0137] wherein, is the analysis signal, is the filtered signal, is a weight, and is a scaling factor.

[0138] Embodiment 34. The encoder (200) of embodiment 33, wherein, is in the range of [0.50 - 1], and is based on a maximum amplification of a low pass filter that generates the filtered signal .

[0139] Embodiment 35. The encoder (200) of any of embodiments 19-34, wherein, in identifying (607, 1109) the wide peaks and the narrow peaks of the combined signal, the memory further contains instructions that, when executed, cause the encoder (200) to perform operations comprising: identifying (1301) the wide peaks and the narrow peaks of the combined signal only at positions of maxima of the filtered analysis signal the analysis signal the analysis signal

[0140] setting (1303) the output of the peak detector at positions of maxima to the combined signal; and

[0141] setting (1305) the output of the peak detector at all other positions to the filtered signal.

[0142] Embodiment 36. A computer program comprising program code to be executed by the processing circuitry (303) of the encoder (200), whereby execution of the program code causes the encoder (200) to perform operations in accordance with any of embodiments 1-17.

[0143] Embodiment 37. A computer program product comprising a non-transitory storage medium comprising program code to be executed by the processing circuitry (303) of the encoder (200), whereby execution of the program code causes the encoder (200) to perform operations in accordance with any of embodiments 1-17.

[0144] Embodiment 38. A method of operating a decoder, the method comprising:

[0145] receiving (601, 1101) a filtered signal of an analysis signal of an audio signal, the analysis signal to be analyzed for peaks;

[0146] combining (605, 1105) the filtered signal with the analysis signal to generate a combined signal using a max function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal; and

[0147] identifying (607, 1109) wide peaks and narrow peaks of the combined signal, wherein the wide peaks and the narrow peaks are characterized by an index i and an amplitude.

[0148] Embodiment 39. The method of embodiment 38, wherein combining (605, 1105) the filtered signal with the analysis signal comprises combining (605, 1105) the filtered signal with the analysis signal in response to determining to identify the wide peaks and the narrow peaks (603, 1107, 1201) using the combined signal.

[0149] Example 40. The method of any of Examples 38-39, wherein receiving the filtered signal of the analysis signal comprises receiving a low-pass filtered signal.

[0150] Example 41. The method of any of Examples 38-40, further comprising determining to use the combined signal based on receiving the indicator.

[0151] Example 42. The method of any of Examples 38-41, wherein receiving the filtered signal comprises receiving a filtered signal having suppressed narrow peaks and wide peaks having amplitudes that are higher than the suppressed narrow peaks.

[0152] Example 43. The method of any of Examples 38-42, further comprising shifting (905) the filtered signal so that peak indices of the filtered signal match peak indices of the analysis signal.

[0153] Example 44. The method of any of Examples 38-43, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0154] Example 45. The method of Example 44, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0155]

[0156] wherein, is the analysis signal, and is the filtered signal.

[0157] Example 46. The method of any of Examples 38-43, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the analysis signal to generate the combined signal using a weighted maximum absolute value at each index i.

[0158] Example 47. The method of Example 46, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0159]

[0160] wherein, is the analysis signal, is the filtered signal, and is a weight.

[0161] Embodiment 48. The method of embodiment 47, wherein, is in the range of [0.50 - 1].

[0162] Embodiment 49. The method of any of embodiments 38-43, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the scaled analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0163] Embodiment 50. The method of embodiment 49, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0164]

[0165] wherein, is the analysis signal, is the filtered signal, and is a scaling factor.

[0166] Embodiment 51. The method of embodiment 50, wherein combining the filtered signal with the scaled analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the scaled analysis signal to generate the combined signal using a weighted maximum absolute value at each index i.

[0167] Embodiment 52. The method of embodiment 51, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0168]

[0169] wherein, is the analysis signal, is the filtered signal, is a weight, and is a scaling factor.

[0170] Embodiment 53. The method of embodiment 52, wherein, is in the range of [0.50 - 1], and is based on a maximum amplification of a low pass filter that generated the filtered signal .

[0171] Embodiment 54. The method of any of embodiments 38-53, wherein identifying (607, 1109) the wide peaks and the narrow peaks of the combined signal comprises identifying only the analysis signal prior to filtering the analysis signal identify (1301) wide peaks and narrow peaks of the combined signal at positions of maxima, the method further comprising:

[0172] setting (1303) an output of the peak detector to the combined signal at positions of maxima; and

[0173] setting (1305) an output of the peak detector to the filtered signal at all other positions.

[0174] Embodiment 55. A decoder (206) adapted for performing according to any of Embodiments 38-54.

[0175] Embodiment 56. A decoder (206) comprising:

[0176] processing circuitry (403); and

[0177] memory (405) coupled with the processing circuitry, wherein the memory includes instructions that, when executed by the processing circuitry, cause the communication device to perform operations comprising:

[0178] receiving (601, 1101) a filtered signal of an analysis signal of an audio signal, the analysis signal to be analyzed for peaks;

[0179] combining (605, 1105) the filtered signal with the analysis signal to generate a combined signal using a max function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal; and

[0180] identifying (607, 1109) wide peaks and narrow peaks of the combined signal, wherein the wide peaks and narrow peaks are characterized by an index i and an amplitude.

[0181] Embodiment 57. The decoder (206) of Embodiment 56, wherein combining (605, 1105) the filtered signal with the analysis signal comprises combining (605, 1105) the filtered signal with the analysis signal in response to determining to identify the wide peaks and narrow peaks using the combined signal (603, 1107, 1201).

[0182] Embodiment 58. The decoder (206) of any of Embodiments 56-57, wherein receiving the filtered signal of the analysis signal comprises receiving a low pass filtered signal.

[0183] Embodiment 59. The decoder (206) of any of Claims 56-58, further comprising determining to use the combined signal based on receiving an indicator.

[0184] Example 60. The decoder (206) of any of Examples 56-59, wherein receiving the filtered signal comprises receiving the filtered signal with suppressed narrow peaks and wide peaks having an amplitude that is higher than the suppressed narrow peaks.

[0185] Example 61. The decoder (206) of any of Examples 56-60, further comprising: shifting (905) the filtered signal so that peak indices of the filtered signal match peak indices of the analysis signal.

[0186] Example 62. The decoder (206) of any of Examples 56-61, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0187] Example 63. The decoder (206) of Example 62, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0188]

[0189] wherein, is the analysis signal, and is the filtered signal.

[0190] Example 64. The decoder (206) of any of Examples 56-63, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the analysis signal to generate the combined signal using a weighted maximum absolute value at each index i.

[0191] Example 65. The decoder (206) of Example 64, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0192]

[0193] wherein, is the analysis signal, is the filtered signal, and is a weight.

[0194] Example 66. The decoder (206) of Example 65, wherein, is in the range of [0.50 - 1].

[0195] Example 67. The decoder (206) of any of Examples 56-63, wherein combining the filtered signal with the analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the scaled analysis signal to generate the combined signal using a maximum absolute value at each index i.

[0196] Example 68. The decoder (206) of Example 67, generating the combined signal using a maximum absolute value at each index i is generated according to:

[0197]

[0198] wherein, is the analysis signal, is the filtered signal, and is a scaling factor.

[0199] Example 69. The decoder (206) of Example 68, wherein combining the filtered signal with the scaled analysis signal to generate the combined signal using a max function comprises combining the filtered signal with the scaled analysis signal to generate the combined signal using a weighted maximum absolute value at each index i.

[0200] Example 70. The decoder (206) of Example 69, wherein generating the combined signal using a maximum absolute value at each index i is generated according to:

[0201]

[0202] wherein, is the analysis signal, is the filtered signal, is a weight, and is a scaling factor.

[0203] Example 71. The decoder (206) of Example 70, wherein, is in the range of [0.50 - 1], and is based on a maximum amplification of a low pass filter that generates the filtered signal .

[0204] Example 72. The decoder (206) of Example 71, wherein, in identifying (607, 1109) the wide peaks and the narrow peaks of the combined signal, the memory further contains instructions that, when executed, cause the decoder (206) to perform operations comprising: only analyzing the analysis signal prior to filtering the analysis signal the wide and narrow peaks of the combined signal at the locations of the maxima, the memory further containing instructions that, when executed, cause the decoder (206) to perform operations comprising:

[0205] setting (1303) the output of the peak detector at the locations of the maxima to the combined signal; and

[0206] setting (1305) the output of the peak detector at all other locations to the filtered signal.

[0207] Embodiment 73. A computer program comprising program code to be executed by a processing circuit (403) of a decoder (206), whereby execution of the program code causes the encoder (200) to perform operations according to any of embodiments 38-55.

[0208] Embodiment 74. A computer program product comprising a non-transitory storage medium, the non-transitory storage medium comprising program code to be executed by a processing circuit (403) of a decoder (206), whereby execution of the program code causes the decoder (206) to perform operations according to any of embodiments 38-55.

[0209] Explanations of various abbreviations / acronyms used in this disclosure are provided below.

[0210] Abbreviation explanations

[0211] FIR Finite Impulse Response

[0212] References are as follows.

[0213] [1] Eric Jacobsen, “On Local Interpolation of DFT Outputs”, http: / / www.ericjacobsen.org / FTinterp.pdf.

[0214] [2] A Nonlinear Lowpass Filter That Eliminates Peak Attenuation, by James McNames and Brahm Goldstein, conference paper in Acoustics, Speech, and Signal Processing, 1988.

[0215] Additional explanations are provided below.

[0216] Generally, unless explicitly stated otherwise and / or as is apparent from the context of the following detailed description, all terms used herein are used in accordance with their plain and ordinary meaning. All references to “one” or “an” element, device, apparatus, component, means, step, etc. means at least one, one and only one, or that a single element, device, apparatus, component, means, step, etc. is to be utilized. All references to “another” any element, device, apparatus, component, means, step, etc. means one or more, one or more and only one, or that a single element, device, apparatus, component, means, step, etc. is to be utilized with at least one other element, device, apparatus, component, means, step, etc. All references to “both” elements, devices, apparatuses, components, means, steps, etc. means both instances of the element, device, apparatus, component, means, step, etc. All references to an element or elements being coupled or linked to or with another element or elements means that the element is either directly coupled or linked to the other element or that one or more intervening elements are present. All references to a step being “after” another step means that the step is directly after the other step or that one or more intervening steps are present. All references to a step being “before” another step means that the step is directly before the other step or that one or more intervening steps are present. All references to an element or elements being “based on” another element or elements means that the element is based both on the other element and on additional elements. All references to a step being “based on” another step means that the step is based both on the other step and on additional steps. Any method disclosed herein can be performed in any suitable order unless otherwise specifically limited and / or unless explicitly claimed. Any feature of any embodiment disclosed herein can be applied to any other embodiment unless specifically stated otherwise. Likewise, any advantage of any embodiment can be applied to any other embodiment, and vice versa. Additional objects, features and advantages will be apparent from the following description of the

[0217] In the above descriptions of various embodiments of the inventive concepts, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concepts. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concepts belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0218] When an element is referred to as being “connected”, “coupled”, “responsive”, or “related” to another element, it can be directly connected, coupled, responsive, or related to the other element, or intervening elements can be present. In contrast, when an element is referred to as being “directly connected”, “directly coupled”, “directly responsive”, or “directly related” to another element, there are no intervening elements present. Like reference numbers refer to like elements throughout. Furthermore, “coupled”, “connected”, “responsive”, or variations thereof, as used herein, can include wireless coupling, connection, or response. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Well-known functions or structures can not have been described in detail in order to not obscure the meaning of the description. The term “and / or” includes any and all combinations of one or more of the associated listed items.

[0219] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements / operations, these elements / operations should not be limited by these terms. These terms are used only to distinguish one element / operation from another. Thus, a first element / operation in some embodiments may be referred to as a second element / operation in other embodiments without departing from the teachings of the inventive concept. Throughout the specification, the same reference numerals or reference symbols denote the same or similar elements.

[0220] As used herein, the terms “comprise,” “comprising,” “comprises,” “include,” “including,” “have,” “has,” or variations thereof are open-ended and include one or more of the stated features, integers, elements, steps, components, or functions, but do not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions, or combinations thereof. Furthermore, as used herein, the common abbreviation “eg” (for example) derives from the Latin phrase “exempligratia,” which can be used to introduce or specify a general example of a previously mentioned item, without being intended as a limitation on that item. The common abbreviation “ie” (i.e.) derives from the Latin phrase “idest,” and can be used to specify a specific item in a broader sense of reference.

[0221] This document describes exemplary embodiments with reference to block diagrams and / or flowcharts illustrating computer-implemented methods, apparatus (systems and / or devices), and / or computer program products. It should be understood that the blocks shown in the block diagrams and / or flowcharts, and combinations of blocks shown in the block diagrams and / or flowcharts, can be implemented by computer program instructions executed by one or more computer circuits. These computer program instructions can be provided to processor circuitry of general-purpose computer circuitry, special-purpose computer circuitry, and / or other programmable data processing circuitry to produce a machine, such that instructions executed via a processor of a computer and / or other programmable data processing apparatus translate and control transistors, values ​​stored in memory locations, and other hardware components within such circuitry to implement the functions / actions specified in the block diagrams and / or flowcharts, thereby creating means (functional bodies) and / or structures for implementing the functions / actions specified in the block diagrams and / or flowcharts.

[0222] These computer program instructions can also be stored in a tangible computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions which implement the function / act specified in the flowchart and / or block diagram block or blocks. Accordingly, embodiments of the inventive concept can be embodied in hardware and / or in software (including firmware, reserve software, microcode, etc.) that runs on a processor such as a digital signal processor, which can collectively be referred to as "circuitry," "a module" or variants thereof.

[0223] It should also be noted that in some alternative implementations, the functions / acts noted in the blocks can occur out of the order noted in the flowcharts. For example, two blocks shown in succession may, in fact, be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality / acts involved. Also, the functionality of a given block can be separated into multiple blocks and / or the functionality of two or more blocks can be combined into a single block. Finally, additional blocks can be added to the flowcharts and / or blocks can be removed therefrom without departing from the scope of the inventive concept. Moreover, while some blocks include arrows on communication paths to indicate primary direction of communication, it is to be understood that communication can occur in the opposite direction to the arrows shown. For example, if the blocks

[0224] Many changes and modifications can be made to the embodiments without departing from the scope of the inventive concept. All such changes and modifications are intended to be included within the scope of the inventive concept. Accordingly, the above-described subject matter is to be considered as illustrative and not restrictive, and the examples of embodiments are intended to cover all such modifications, enhancements, and other embodiments falling within the spirit and scope of the inventive concept. Thus, the scope of the inventive concept should be determined by the broadest interpretation of the appended disclosure and the principles, aspects and embodiments of the inventive concept, viewed in conjunction with the section entitled "Scope of the Invention Concept" and any other sections included herein.

Claims

1. A method for operating an encoder, the method comprising: The system receives an analysis signal of (601, 1101) audio signals and a filtered signal generated by filtering the analysis signal. The filtered signal and the analyzed signal are combined (605, 1105) using a maximum value function to generate a combined signal by finding the maximum absolute value of the filtered signal and the analyzed signal at each index i of the combined signal; and Identify the broad peak and narrow peak of the combined signal (607, 1109), wherein the broad peak and the narrow peak are characterized by the index i and the amplitude.

2. The method according to claim 1, wherein, Combining the filtered signal with the analysis signal (605, 1105) includes: in response to determining that the combined signal is used to identify broad peaks and narrow peaks (603, 1107, 1201), combining the filtered signal with the analysis signal (605, 1105).

3. The method according to claim 1, wherein, The filtered signal for receiving the analysis signal includes: receiving a low-pass filtered signal.

4. The method according to claim 1, further comprising: The use of the combined signal is determined based on the received indicator.

5. The method according to claim 1, wherein, Receiving the filtered signal includes receiving a filtered signal having a suppressed narrow peak and a wide peak with an amplitude higher than the suppressed narrow peak.

6. The method according to claim 1, further comprising: The filtered signal is shifted (1105) such that the peak index of the filtered signal matches the peak index of the analyzed signal.

7. The method according to any one of claims 1 to 6, wherein, Combining the filtered signal and the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal and the analyzed signal using the maximum absolute value at each index i to generate a combined signal.

8. The method according to claim 7, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, and It is the filtered signal.

9. The method according to any one of claims 1 to 6, wherein, Combining the filtered signal and the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal and the analyzed signal using the weighted maximum absolute value at each index i to generate a combined signal.

10. The method according to claim 9, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, and It's the weight.

11. The method according to claim 10, wherein, It is greater than or equal to 0.5 and less than 1.

12. The method according to any one of claims 1 to 6, wherein, Combining the filtered signal with the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal with the scaled analyzed signal using the maximum absolute value at each index i to generate a combined signal.

13. The method according to claim 12, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, and It is the scaling factor, where, Based on the generation of the filtered signal The maximum amplification of the low-pass filter.

14. The method according to claim 13, wherein, Combining the filtered signal with the scaled analysis signal using a maximum value function to generate a combined signal includes: combining the filtered signal with the scaled analysis signal using the weighted maximum absolute value at each index i to generate a combined signal.

15. The method according to claim 14, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, It is weight, and It is the scaling factor.

16. The method according to claim 15, wherein, It is greater than or equal to 0.5 and less than 1.

17. The method according to any one of claims 1 to 6, wherein, Combining the filtered signals includes: filtering only the analyzed signals. The previously mentioned analysis signal The maximum value of the filtered signal is combined at the location of (1301).

18. An encoder (200) comprising: Processing circuit (303); as well as A memory (305), coupled to the processing circuitry, includes instructions that, when executed by the processing circuitry, cause the encoder to perform operations including the following steps: The system receives an analysis signal of (601, 1101) audio signals and a filtered signal generated by filtering the analysis signal. The filtered signal and the analyzed signal are combined (605, 1105) using a maximum value function to generate a combined signal by finding the maximum absolute value of the filtered signal and the analyzed signal at each index i of the combined signal; and Identify the broad peak and narrow peak of the combined signal (607, 1109), wherein the broad peak and the narrow peak are characterized by the index i and the amplitude.

19. The encoder (200) according to claim 18, wherein, Combining the filtered signal with the analysis signal (605, 1105) includes: in response to determining (603, 1107, 1201) to use the combined signal to identify broad peaks and narrow peaks, combining the filtered signal with the analysis signal (605, 1105).

20. The encoder (200) according to claim 18, wherein, The filtered signal for receiving the analysis signal includes: receiving a low-pass filtered signal.

21. The encoder (200) according to claim 18, further comprising: The filter to be used is determined based on the received filter indicator.

22. The encoder (200) according to claim 18, wherein, Receiving the filtered signal includes receiving a filtered signal having a suppressed narrow peak and a wide peak with an amplitude higher than the suppressed narrow peak.

23. The encoder (200) according to claim 18, further comprising: The filtered signal is shifted (905) such that the peak index of the filtered signal matches the peak index of the analyzed signal.

24. The encoder (200) according to any one of claims 18 to 23, wherein, Combining the filtered signal and the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal and the analyzed signal using the maximum absolute value at each index i to generate a combined signal.

25. The encoder (200) according to claim 24, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, and It is the filtered signal.

26. The encoder (200) according to any one of claims 18 to 23, wherein, Combining the filtered signal and the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal and the analyzed signal using the weighted maximum absolute value at each index i to generate a combined signal.

27. The encoder (200) according to claim 26, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, and It's the weight.

28. The encoder (200) according to claim 27, wherein, It is greater than or equal to 0.5 and less than 1.

29. The encoder (200) according to any one of claims 18 to 23, wherein, Combining the filtered signal with the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal with the scaled analyzed signal using the maximum absolute value at each index i to generate a combined signal.

30. The encoder (200) according to claim 29, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, and It is the scaling factor, where, Based on the generation of the filtered signal The maximum amplification of the low-pass filter.

31. The encoder (200) according to claim 30, wherein, Combining the filtered signal with the scaled analysis signal using a maximum value function to generate a combined signal includes: combining the filtered signal with the scaled analysis signal using the weighted maximum absolute value at each index i to generate a combined signal.

32. The encoder (200) according to claim 31, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, It is weight, and It is the scaling factor.

33. The encoder (200) according to claim 32, wherein, It is greater than or equal to 0.5 and less than 1.

34. The encoder (200) according to any one of claims 18 to 23, wherein, When identifying the broad peak and the narrow peak of the combined signal (607, 1109), the memory also contains instructions that, when executed, cause the encoder (200) to perform an operation including the following steps: filtering only the analyzed signal. The previously mentioned analysis signal The memory also contains instructions that, when executed, cause the encoder (200) to perform operations including the following steps: (1301) Identify the wide peak and the narrow peak of the combined signal at the location of the maximum value. At the location of the maximum value, the output of the peak detector is set (1303) to the combined signal; and At all other locations, the output of the peak detector is set (1305) to the filtered signal.

35. A computer program product comprising a non-transitory storage medium, the non-transitory storage medium comprising program code to be executed by a processing circuitry (303) of an encoder (200), wherein execution of the program code causes the encoder (200) to perform the operation according to any one of claims 1 to 17.

36. A method of operating a decoder, the method comprising: The system receives an analysis signal of (601, 1101) audio signals and a filtered signal generated by filtering the analysis signal. The filtered signal and the analyzed signal are combined (605, 1105) using a maximum value function to generate a combined signal by finding the maximum absolute value of the filtered signal and the analyzed signal at each index i of the combined signal; and Identify the broad peak and narrow peak of the combined signal (607, 1109), wherein the broad peak and the narrow peak are characterized by the index i and the amplitude.

37. The method of claim 36, wherein, Combining the filtered signal with the analysis signal (605, 1105) includes: in response to determining that the combined signal is used to identify broad peaks and narrow peaks (603, 1107, 1201), combining the filtered signal with the analysis signal (605, 1105).

38. The method according to claim 36, wherein, The filtered signal for receiving the analysis signal includes: receiving a low-pass filtered signal.

39. The method of claim 36, further comprising: The use of the combined signal is determined based on the received indicator.

40. The method of claim 36, wherein, Receiving the filtered signal includes receiving a filtered signal having a suppressed narrow peak and a wide peak with an amplitude higher than the suppressed narrow peak.

41. The method of claim 36, further comprising: The filtered signal is shifted (905) such that the peak index of the filtered signal matches the peak index of the analyzed signal.

42. The method according to any one of claims 36 to 41, wherein, Combining the filtered signal and the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal and the analyzed signal using the maximum absolute value at each index i to generate a combined signal.

43. The method according to claim 42, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, and It is the filtered signal.

44. The method according to any one of claims 36 to 41, wherein, Combining the filtered signal and the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal and the analyzed signal using the weighted maximum absolute value at each index i to generate a combined signal.

45. The method according to claim 44, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, and It's the weight.

46. ​​The method according to claim 45, wherein, It is greater than or equal to 0.5 and less than 1.

47. The method according to any one of claims 36 to 41, wherein, Combining the filtered signal with the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal with the scaled analyzed signal using the maximum absolute value at each index i to generate a combined signal.

48. The method according to claim 47, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, and It is the scaling factor, where, Based on the generation of the filtered signal The maximum amplification of the low-pass filter.

49. The method according to claim 48, wherein, Combining the filtered signal with the scaled analysis signal using a maximum value function to generate a combined signal includes: combining the filtered signal with the scaled analysis signal using the weighted maximum absolute value at each index i to generate a combined signal.

50. The method according to claim 49, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, It is weight, and It is the scaling factor.

51. The method according to claim 50, wherein, It is greater than or equal to 0.5 and less than 1.

52. The method according to any one of claims 36 to 41, wherein, Identifying the broad peak and the narrow peak of the combined signal (607, 1109) includes: only filtering the analysis signal The previously mentioned analysis signal The method further includes identifying the broad peak and the narrow peak of the combined signal at the location of the maximum value (1301). At the location of the maximum value, the output of the peak detector is set (1303) to the combined signal; and At all other locations, the output of the peak detector is set (1305) to the filtered signal.

53. A decoder (206) comprising: Processing circuit (403); as well as A memory (405), coupled to the processing circuitry, wherein the memory includes instructions that, when executed by the processing circuitry, cause the decoder to perform operations including the following steps: The system receives an analysis signal of (601, 1101) audio signals and a filtered signal generated by filtering the analysis signal. The filtered signal and the analyzed signal are combined (605, 1105) using a maximum value function to generate a combined signal by finding the maximum absolute value of the filtered signal and the analyzed signal at each index i of the combined signal; and Identify the broad peak and narrow peak of the combined signal (607, 1109), wherein the broad peak and the narrow peak are characterized by the index i and the amplitude.

54. The decoder (206) according to claim 53, wherein, Combining the filtered signal with the analysis signal (605, 1105) includes: in response to determining that the combined signal is used to identify broad peaks and narrow peaks (603, 1107, 1201), combining the filtered signal with the analysis signal (605, 1105).

55. The decoder (206) according to claim 53, wherein, The filtered signal for receiving the analysis signal includes: receiving a low-pass filtered signal.

56. The decoder (206) according to claim 53 further comprises: The use of the combined signal is determined based on the received indicator.

57. The decoder (206) according to claim 53, wherein, Receiving the filtered signal includes receiving a filtered signal having a suppressed narrow peak and a wide peak with an amplitude higher than the suppressed narrow peak.

58. The decoder (206) according to claim 53 further comprises: The filtered signal is shifted (905) such that the peak index of the filtered signal matches the peak index of the analyzed signal.

59. The decoder (206) according to any one of claims 53 to 58, wherein, Combining the filtered signal and the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal and the analyzed signal using the maximum absolute value at each index i to generate a combined signal.

60. The decoder (206) according to claim 59, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, and It is the filtered signal.

61. The decoder (206) according to any one of claims 53 to 58, wherein, Combining the filtered signal and the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal and the analyzed signal using the weighted maximum absolute value at each index i to generate a combined signal.

62. The decoder (206) according to claim 61, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, and It's the weight.

63. The decoder (206) according to claim 62, wherein, It is greater than or equal to 0.5 and less than 1.

64. The decoder (206) according to any one of claims 53 to 58, wherein, Combining the filtered signal with the analyzed signal using a maximum value function to generate a combined signal includes: combining the filtered signal with the scaled analyzed signal using the maximum absolute value at each index i to generate a combined signal.

65. The decoder (206) according to claim 64, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, and It is the scaling factor, where, Based on the generation of the filtered signal The maximum amplification of the low-pass filter.

66. The decoder (206) according to claim 65, wherein, Combining the filtered signal with the scaled analysis signal using a maximum value function to generate a combined signal includes: combining the filtered signal with the scaled analysis signal using the weighted maximum absolute value at each index i to generate a combined signal.

67. The decoder (206) according to claim 66, wherein, The combined signal is generated using the maximum absolute value at each index i according to the following formula: in, It is the analyzed signal, It is the filtered signal, It is weight, and It is the scaling factor.

68. The decoder (206) according to claim 67, wherein, It is greater than or equal to 0.5 and less than 1.

69. The decoder (206) according to claim 68, wherein, When identifying the broad peak and the narrow peak of the combined signal (607, 1109), the memory also contains instructions that, when executed, cause the decoder (206) to perform an operation including the following steps: filtering only the analyzed signal The previously mentioned analysis signal The memory also contains instructions that, when executed, cause the decoder (206) to perform operations including the following steps: (1301) Identify the wide peak and the narrow peak of the combined signal at the location of the maximum value. At the location of the maximum value, the output of the peak detector is set (1303) to the combined signal; and At all other locations, the output of the peak detector is set (1305) to the filtered signal.

70. A computer program product comprising a non-transitory storage medium, the non-transitory storage medium comprising program code to be executed by processing circuitry (403) of a decoder (206), wherein execution of the program code causes the decoder (206) to perform the operation according to any one of claims 36 to 52.

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