# US 12,002,477 B2 · Methods for phase ECU F0 interpolation split and related controller

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- Number: US 12,002,477 B2
- Document ID: US12002477B2
- Status: Granted
- Kind: B2
- Application number: 18/203,280
- Filed: 2023-05-30
- Published: 2023-09-21
- Granted: 2024-06-04
- Earliest claimed: 2019-02-21
- Assignees: Telefonaktiebolaget LM Ericsson (publ)
- Applicants: Telefonaktiebolaget LM Ericsson (publ)
- Inventors: Martin Sehlstedt
- Web page: https://patentgrep.com/patent/US12002477B2

## CPC

- G10L 19/005: Correction of errors induced by the transmission channel, if related to the coding algorithm
- G06F 17/142: {Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm}
- G10L 19/02: using spectral analysis, e.g. transform vocoders or subband vocoders
- G10L 19/0204: {using subband decomposition}
- G10L 19/0212: {using orthogonal transformation}
- G10L 25/18: the extracted parameters being spectral information of each sub-band
- G10L 25/45: characterised by the type of analysis window
- H04L 65/75: Media network packet handling
- H04L 65/80: Responding to QoS
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Controlling a concealment method for a lost audio frame associated with a received audio signal is provided. At least one bin vector of a spectral representation for at least one tone is obtained, wherein the at least one bin vector includes three consecutive bin values for the at least one tone. Whether each of the three consecutive bin values has a complex value or a real value is determined. Responsive to the determination, the three consecutive bin values are processed to estimate a frequency of the at least one tone based on whether each bin value has a complex value or a real value.

## Claims

### Claim 1

A method for controlling a concealment method for a lost audio frame associated with a received audio signal, the method comprising:
obtaining at least one bin vector of a spectral representation for at least one tone, wherein the at least one bin vector includes three consecutive bin values for the at least one tone; and
responsive to whether each of the three consecutive bin values has a complex value or a real value, selecting an interpolation method to estimate a frequency of the at least one tone using the three consecutive bin values.

### Claim 2 (depends on 1)

The method of claim 1, wherein when each of the three consecutive bin values for the at least one tone has a complex value:
extracting a complex value coefficient for each of the three consecutive bin values;
calculating a fractional bin offset for the at least one tone based on the complex valued coefficient of each of the three consecutive bin values; and
calculating a bin frequency for the at least one tone based on the fractional bin offset.

### Claim 3 (depends on 2)

The method of claim 2, wherein calculating the fractional bin offset for the at least one tone comprises calculating the fractional bin offset for the at least one tone based a scaling coefficient, a window function used for the spectral representation, and a transform length for a frequency spectrum containing each of the three consecutive bin values for the at least one tone.

### Claim 4 (depends on 3)

The method of claim 3, wherein the scaling coefficient depends on a type of window function.

### Claim 5 (depends on 2)

The method of claim 2, wherein calculating the fractional bin offset for the at least one tone comprises calculating the fractional bin offset for the at least one tone based on a window function and a transform length for a frequency spectrum containing each of the three consecutive bin values.

### Claim 6 (depends on 5)

The method of claim 5, wherein calculating the fractional bin offset comprises calculating the fractional bin offset according to:
fk=(k+δ)C
wherein fk is the fractional bin offset for peak location k, δ is an interpolation value, and C is a coarse resolution in Hz/bin.

### Claim 7 (depends on 6)

The method of claim 6 wherein δ is determined according to:
δ
=
K
j
⁢
a
⁢
c
⁢
o
⁢
b
⁢
RE
⁢
{
X
k
-
1
-
X
k
+
1
2
⁢
X
k
-
X
k
-
1
-
X
k
+
1
}
where Kjacob is a scaling coefficient and Xk−1, Xk, and Xk+1 are complex-valued coefficients for the at least one tone at k.

### Claim 8 (depends on 1)

The method of claim 1, further comprising when at least one of the three consecutive bin values has a real value:
extracting a magnitude point for each of the three consecutive bin values;
calculating a fractional bin offset based on the magnitude points for each of the three consecutive bin values; and
calculating a bin frequency for the at least one tone based on the fractional bin offset.

### Claim 9

An apparatus for controlling a concealment method for a lost audio frame associated with a received audio signal, the apparatus comprising:
processing circuitry; and
memory coupled with the processing circuitry, wherein the memory includes instructions that when executed by the processing circuitry causes the apparatus to perform operations comprising:
obtaining at least one bin vector of a spectral representation for at least one tone, wherein the at least one bin vector includes three consecutive bin values for the at least one tone; and
responsive to whether each of the three consecutive bin values has a complex value or a real value, selecting an interpolation method to estimate a frequency of the at least one tone using the three consecutive bin values.

### Claim 10 (depends on 9)

The apparatus of claim 9 wherein the memory includes further instructions that when executed by the processing circuitry causes the apparatus to perform operations comprising:
when each of the three consecutive bin values for the at least one tone has a complex value:
extracting a complex value coefficient for each of the three consecutive bin values;
calculating a fractional bin offset for the at least one tone based on the complex valued coefficient of each of the three consecutive bin values; and
calculating a bin frequency for the at least one tone based on the fractional bin offset.

### Claim 11 (depends on 10)

The apparatus according to claim 10, wherein in calculating the fractional bin offset for the at least one tone, the memory includes further instructions that when executed by the processing circuitry causes the apparatus to perform operations comprising:
calculating the fractional bin offset for the at least one tone based a scaling coefficient, a window function used for the spectral representation, and a transform length for a frequency spectrum containing each of the three consecutive bin values for the at least one tone.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the scaling coefficient depends on a type of window function.

### Claim 13 (depends on 10)

The apparatus of claim 10, wherein calculating the fractional bin offset for the at least one tone, the memory includes further instructions that when executed by the processing circuitry causes the apparatus to perform operations comprising:
calculating the fractional bin offset for the at least one tone based on a window function and a transform length for a frequency spectrum containing each of the three consecutive bin values.

### Claim 14 (depends on 13)

The apparatus of claim 13, wherein calculating the fractional bin offset comprises calculating the fractional bin offset according to:
fk=(k+δ)C
wherein fk is the fractional bin offset for peak location k, δ is an interpolation value, and C is a coarse resolution in Hz/bin.

### Claim 15 (depends on 14)

The apparatus of claim 14 wherein δ is determined according to:
δ
=
K
j
⁢
a
⁢
c
⁢
o
⁢
b
⁢
RE
⁢
{
X
k
-
1
-
X
k
+
1
2
⁢
X
k
-
X
k
-
1
-
X
k
+
1
}
where Kjacob is a scaling coefficient and Xk−1, Xk, and Xk+1 are complex-valued coefficients for the at least one tone at k.

### Claim 16 (depends on 9)

The apparatus of claim 9, wherein the memory includes further instructions that when executed by the processing circuitry causes the apparatus to perform operations further comprising:
when at least one of the three consecutive bin values has a real value:
extracting a magnitude point for each of the three consecutive bin values;
calculating a fractional bin offset based on the magnitude points for each of the three consecutive bin values; and
calculating a bin frequency for the at least one tone based on the fractional bin offset.

### Claim 17

A non-transitory computer readable medium having program code to be executed by at least one processor of a decoder for controlling a concealment method for a lost audio frame associated with a received audio signal, whereby execution of the program code causes the decoder to perform operations comprising:
obtaining at least one bin vector of a spectral representation for at least one tone, wherein the at least one bin vector includes three consecutive bin values for the at least one tone; and
responsive to whether each of the three consecutive bin values has a complex value or a real value, selecting an interpolation method to estimate a frequency of the at least one tone using the three consecutive bin values.

### Claim 18 (depends on 17)

The non-transitory computer readable medium of claim 17, having further program code to be executed by the at least one processor, whereby execution of the further program code causes the decoder to perform operations comprising:
wherein when each of the three consecutive bin values for the at least one tone has a complex value:
extracting a complex value coefficient for each of the three consecutive bin values;
calculating a fractional bin offset for the at least one tone based on the complex valued coefficient of each of the three consecutive bin values; and
calculating a bin frequency for the at least one tone based on the fractional bin offset.

### Claim 19 (depends on 18)

The non-transitory computer readable medium of claim 18, wherein calculating the fractional bin offset for the at least one tone comprises calculating the fractional bin offset for the at least one tone based a scaling coefficient, a window function used for the spectral representation, and a transform length for a frequency spectrum containing each of the three consecutive bin values for the at least one tone.

### Claim 20 (depends on 17)

The non-transitory computer readable medium of claim 17 having further program code to be executed by at least one processor of a decoder for controlling a concealment method for a lost audio frame associated with a received audio signal, whereby execution of the further program code causes the decoder to perform operations comprising:
when at least one of the three consecutive bin values has a real value:
extracting a magnitude point for each of the three consecutive bin values;
calculating a fractional bin offset based on the magnitude points for each of the three consecutive bin values; and
calculating a bin frequency for the at least one tone based on the fractional bin offset.