Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim(s) 1-4 is/are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Norvell et al (US 20220059099 A1).
As per claim 1, A decorrelator comprising:
a plurality of delay units (fig.7, para. 51: output of DFT is in subband form noting the function in equation 6 is per k, or per subband, therefore decorrelator stage 730 comprises an input/delay unit for each subband, where each decorrelator comprises an allpass filter/delay unit per para 58),
wherein each delay unit is configured for receiving a part of a frequency representation being based on an audio signal (the subbands output from DFT stage);
wherein each delay unit is configured for delaying the received part individually when compared to other delay units (the delay and allpass stages each apply delays independantly to each subband because each subband is an independent channel) and to provide a delayed part (either of the delay or allpass stages will delay the input subbands); and
an envelope shaper (745,755,760) configured:
for receiving (input to 745 from 730) and combining signals (755) being based on the delayed parts of the frequency representation;
for receiving the frequency representation of the audio signal (input from DFT to 760);
for adjusting an energy of the delayed parts in respect of the frequency representation of the audio signal (the functions of either 755 and or 760 will adjust the energy of the subbands k/frequency representation); and
for providing a combined shaped frequency representation (output from 760).
As per claim 2, the decorrelator of claim 1, wherein different parts of the frequency representation comprise a same or a different number of frequency bins (para. 67: The approximate phase adjustment can be used on a band basis and/or on a per frequency bin basis, where different parts will satisfy the limitation ‘same or different number’ regardless of the relative number of bins).
As per claim 3, The decorrelator of claim 1, further comprising a phase shifter configured for
phase shifting the frequency representation of the audio signal (the allpass filters para 58, will phase shift the frequency representation, or can be in the time domain before the dft );
or
for phase shifting the audio signal in a time domain to acquire a phase shifted audio signal (not mapped, however noting para. 58: or can be in the time domain before the dft).
As per claim 4, the decorrelator of claim 3, wherein the phase shifter is configured for phase shifting the frequency representation of the audio signal (per claim 3 rejection) and
comprises a plurality of allpass filters of the decorrelator, para 58 (the respective allpass filters as applied to each subband k),
wherein each allpass filter is configured for phase shifting an associated part of the frequency representation of the audio signal (the processing is in subband form per (k), the decorrelator comprises respective allpass filters for each subband which shifts each associated frequency representation/band).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 5-32,34-41 is/are rejected under 35 U.S.C. 103 as being unpatentable over Norvell et al (US 20220059099 A1).
As per claim 5, Norvell discloses the decorrelator of claim 4, but does not disclose:
wherein an allpass filter of the plurality of allpass filter comprises a set of allpass filter structures such as Schroeder IIR filters, being serially connected to each other;
wherein the allpass filter structures are adapted for providing different time delays;
or
wherein the allpass filter structures comprise a nested allpass filter structure.
The examiner takes official notice it is well known in the art that decorrelators can use Schroeders well known nested All-pass reverberator for the purpose of conforming to well known standards in order to decorrelate the signals.
Wherein, the Schroeder nested allpass filter structure comprises: wherein an allpass filter of the plurality of allpass filter comprises a set of allpass filter structures such as Schroeder IIR filters, being serially connected to each other;
wherein the allpass filter structures comprise a nested allpass filter structure (per the well known nest allpass structure of Schroeder ).
Note: wherein the allpass filter structures are adapted for providing different time delays; is not mapped as recited in the alternative
As per claim 6, the decorrelator of claim 5, wherein a number of allpass filter structures in the set and/or a circuitry of the allpass filter structure is equal or different between different allpass filters (any implementation of the allpass filter structure per the claim 5 rejection will meet the limitation equal or different regardless of the relative number of allpass filter structures).
As per claim 7, the decorrelator of claim 5, wherein the different time delays are based on a prime number multiple of a local sampling rate used for acquiring the frequency representation of the audio signal (not mapped as drawn to not selected alternative in parent claim 5).
As per claim 8, Norvell discloses the decorrelator of claim 5, but does not specify wherein the set of allpass filter structures comprises a number of four allpass filter structures and are adapted for providing a delay of 1, 2, 3 and 5 or 1, 3, 5 and 7, respectively (each nested delay creates an additional clock cycle/units in a zdomain.
It would have been obvious to one skilled in the art to implement the number of delay lines as comprising at least 4, as desired, as a matter of design choice, as a tradeoff between filter processing cost versus improves impulse response. Noting that, in the Schroeder all pass filters the delay-line lengths are typically mutually prime and spanning successive orders which would mean 1,3,5,7 clock cycles/units in a z domain .
As per claim 9, Norvell discloses the decorrelator of claim 4, but does not specify wherein a gain factor of the allpass filter is adapted to a value with a magnitude of 0.7 within a tolerance range of e.g., 20 %.
It would have been obvious to one skilled in the art that the gain value of one of the all pass filters could be 0.7 tolerance 20% for the purpose of decorrelating the desired portions of the particular input signals.
As per claim 10, the decorrelator of claim 3,
wherein the phase shifter is configured for phase shifting the audio signal in a time domain (note the 112 rejection above, and the alternative cited in claim 3);
wherein the phase shifter comprises a set of allpass filter structures such as Schroeder IIR filters, being serially connected to each other (per claim 5 rejection);
wherein the allpass filter structures are adapted for providing different time delays (per claim 5 rejection);
or
wherein the allpass filter structures comprise a nested allpass filter structure (per claim 5 rejection).
As per claim 11, the decorrelator of claim 10, wherein the different time delays are based on a prime number multiple of a clock rate of the dsp performing the cited functions and based on reciprocal of a sampling rate used for acquiring the frequency representation of the audio signal because those are the inputs to the allpass time delays.
As per claim 12, the decorrelator of claim 10, wherein the different time delays are based on a prime number being acquired by multiplying each of a set of minimal prime numbers, e.g., 1, 2, 3 and 5; or 1, 3, 5 and 7, with a downsampling factor used for generating the parts of the frequency representation of the audio signal to acquire an intermediate result; and
for using a next prime number with respect to the intermediate result, e.g., as 131, 257, 383, 641 or 131, 383, 641, 907.
(as per the claim 8 rejection)
As per claim 13, the decorrelator of claim 10, comprising a first
conversion unit for acquiring the frequency representation of the audio signal from the audio signal for the envelope shaper (DFT stage going into 730); and
comprising a second conversion unit for acquiring a frequency representation from a reverberated audio signal (DFT receiving from 735);
wherein the parts of the frequency representation form parts of the frequency representation from the reverberated audio signal (the output of the DFT near 735 is the residual/reverberated signal).
As per claim 14, the decorrelator of claim 1, wherein the parts of the frequency representation comprise an equal or different number of frequency bins (per the claim 2 rejection).
As per claim 15, the decorrelator of claim 1, being adapted for acquiring a number of parts of the frequency representation (the subbands/bins are acquired per the DFT stages).
As per claim 16, Norvell discloses the decorrelator of claim 1, but does not specify it being adapted for acquiring the frequency representation with a number of 128 or 129 frequency bins.
The examiner takes official notice it would have been obvious to one skilled in the art to organize the number of bands and bins into a desired number, including 128 or 129 bins as a matter of design choice for the purpose of designing to the particular set of inputs signals and band resolution required and allowed by processing resources.
As per claim 17, the decorrelator of claim 1, wherein the decorrelator is adapted to additionally implement a same and predefined delay for a subset or all parts of the frequency representation (The entire frequency representation must be delayed with a same predefined delay to account for the processing time in order to synchronize the inputs into stage 730).
As per claim 18, decorrelator of claim 1, wherein the delay units associated to a spectral part of the plurality of delay units are configured for delaying the associated part of the frequency representation differently when compared to delay units associated to other spectral parts (individual band and bind needs a respective and different delay in order to synchronize the bands from the DFT in order to be input into the subsequent stages as shown in fig. 7).
As per claim 19, the decorrelator of claim 1, wherein the plurality of delay units is configured for delaying parts of the frequency representation comprising lower frequencies with a higher time delay when compared to parts of the frequency representation comprising higher frequencies (larger frequencies by definition require longer wavelengths, numbers of samples, and respective delays compared to the shorter, faster higher frequencies).
As per claim 20, The decorrelator of claim 19, wherein a relationship between different time delays is one of linear, logarithmic and/or based on a rounding on subband samples (the Schroeder all pass as per the claim 5 rejection has a linear relationship between time delays as they are used to synchronize a number of bins/subbands that increase linearly ).
As per claim 21, the decorrelator of claim 1, comprising a conversion unit for receiving and converting the audio signal or a reverberated version of the audio signal into the parts by performing a time-block-wise discrete Fourier transform,
DFT (the DFT stages in fig. 7),
or
Short-time Fourier transform, STFT;
However, Norvell does not specify the
wherein the conversion unit is configured for converting blocks with an overlap of 50 % within a tolerance range.
Norvel teaches to design the overlap as a tradeoff with processor resource/algorithmic delay (para. 52) , where it would be obvious to design the overlap if 50% with a tolerance for the purpose of designing to the cited tradeoff.
As per claim 22, the decorrelator of claim 1, comprising a conversion unit for receiving and converting the audio signal or a reverberated version of the audio signal into the parts by performing a time-block-wise discrete Fourier transform,
DFT (per the claim 21 rejection),
or
Short-time Fourier transform, STFT (not mapped);
However, Norvell does not specify the
wherein blocks comprise a block length of 256 samples.
Norvel teaches to design the overlap as a tradeoff with processor resource/algorithmic delay (para. 52) , where it would be obvious to design the block length of 256 samples for the purpose of designing to the cited tradeoff.
As per claim 23, the decorrelator of claim 1, comprising an inverse conversion unit for receiving processed versions of the parts of the frequency representation and for synthesizing an synthesized signal from the processed versions based on an overlap add procedure (the IDFT for ch1 and ch2 in fig. 7).
As per claim 24, the decorrelator of claim 1, wherein the envelope shaper is configured for operating in a subband domain (stage 745 is in the subband domain). However Norvell does not specify
with a temporal resolution of less than 4 ms.
It would have been obvious to one skilled in the art to design clock cycles/temporal resolution for less than 4ms as a matter of design choice for the purpose of optimizing the available processing resources/clocking to the required timing of the disclosed functions which must all be synchronized in order to function as disclosed.
As per claim 25, The decorrelator of claim 1 comprising an interface for providing a signal based on the combined shaped frequency representation (the output of 760).
As per claim 26, the decorrelator of claim 1, wherein the envelope shaper is to shape spectral bins
in time
and/or
in frequency individually
or
as a group, e.g., by implementing an interdependent or an at least groupwise common shaping processing.
(shape in frequency individually per band/bin per stage 745):
As per claim 27, the decorrelator of claim 1, comprising a signal processing stage configured for receiving a signal based on the combined shaped frequency representation as a mono signal (output of 755 is a downmix/mono signal) and
for processing the mono signal at least to a stereo signal (which is processed to a multichannel signal, ie. At least stereo per stage 760).
As per claim 28, the decorrelator of claim 1, comprising a signal processing stage configured for
processing the combined shaped frequency representation at least to a stereo audio signal (per stage 760, which output at least stereo); and
for source extend modelling based on the at least stereo signal, e.g., in the frequency domain (the source extension modelling based on the output of 750).
As per claim 29, Norvell discloses a processing system comprising: a decorrelator according to claim 1 (as per the claim 1 rejection); a processing stage(the processing along with the decorrelator in fig. 7 ) for transforming a mid/side decomposed signal (to produce mid signal at 715 and a side signal at 735 to a left/right decomposed signal output of 760).
As per claim 30, the processing system of claim 29, wherein one portion of the mid/side decomposed signal is provided by the decorrelator (output of 730) and
the other portion is provided by a delay compensation unit 750 being connected in parallel with the decorrelator and connected with the processing stage (as shown in fig. 7).
As per claim 31, The processing system of claim 30, comprising a transient suppressor configured for detecting a transient in the audio signal or the frequency representation thereof at an input of the decorrelator;
wherein the transient suppressor is configured for temporarily muting the portion provided by the decorrelator (via BF1, and the concealment frame para 57 ) to suppress echoes (suppressing bad frames will suppress echoes from those frames) at the processing stage (the lost or corrupted frame/transient detector per para 57).
As per claim 32, the processing system of claim 31, wherein the transient suppressor is configured for amplifying the portion of the delay compensation unit corresponding to muting the portion of the decorrelator (the concealment frame is generated/amplified and applied to the audio frames per para 57).
As per claim 34, the processing system of claim 31, wherein the transient suppressor is configured for suppressing a detected transient and for suppressing a following transient not earlier than a predefined inhibition time (all bad frames/transients including a detected transient and a following transient are suppressed as detected per para 57, where the detection, since it is digital, cannot occur during an inhibition time which is the length of time between clock pulses, where a subsequent processing step, such as suppressing, cannot occur until; a clock pulse has occurred, which includes the predefined inhibition time of the length of time until the clock cycle has been recognized by the dsp) (furthermore, the examiner notes that hysteresis in transient processing is another well known function).
As per claim 35, the processing system of claim 31, wherein the inhibition time is a first inhibition time; wherein the transient suppressor is configured for restarting the inhibition time as a second inhibition time being longer than the first inhibition time in case a transient occurs during the first inhibition time (everytime a transient occurs, there is an inhibition time first, second ect, where the inhibition time restarts from the time of the transient, until the time it can actually be processed as disclosed, per clock cycle, which defines inhibition times based on clock cycles).
As per claim 36, the processing system of claim 30, further comprising a transient suppressor configured for detecting a transient in the audio signal at an input of the decorrelator,wherein the transient suppressor is configured for temporarily muting the portion provided by the decorrelator to suppress echoes at the processing stage, and (per the claim 31 rejection via BF1 going into stage 760 and the concealment frame per para 56).
As per claim 37, the processing system of claim 31, wherein the transient suppressor is configured for muting the portion of the decorrelator for a longer time when compared to a pre-delay of the decorrelator (the concealment frame must be inserted/the portion muted longer than the predelay of the decorrelator 730, in order for the frame to effectively conceal the transient/bad frame.
As per claim 38, the processing system of claim 29, wherein the decorrelator is to provide the combined shaped frequency representation as a part of the mid/side decomposed signal to the processing stage 760; and
the processing stage is to transform the combined shaped frequency representation (output of 755) and a delayed version of the audio signal (output of 7625 or DFT into stage 760) to the left/right decomposed signal in the frequency domain (output of 760).
As per claim 39, a method comprising:
receiving a plurality of parts of a frequency representation being based on an audio signal (the bands/bins per the claim 1 rejection);
individually delaying each of the received parts to provide a plurality of delayed parts (delay units per the individual subbands per the the claim 1 rejection); and
receiving and combining signals being based on the delayed parts of the frequency representation (745,755);
receiving the frequency representation of the audio signal (output of DFT);
adjusting an energy of the delayed parts in respect of the frequency representation of the audio signal (stage 745); and providing a combined shaped frequency representation (output 755).
As per claim 40, the method of claim 39, further comprising:
detecting a transient in the audio signal or the frequency representation thereof;
temporarily muting a portion provided by a decorrelator to suppress echoes at a processing stage. (per claim 31 rejection).
As per claim 41, a non-transitory digital storage medium having a computer program stored thereon to perform the method comprising:
receiving a plurality of parts of a frequency representation being based on an audio signal (fig. 7 the DFT stage);
individually delaying each of the received parts to provide a plurality of delayed parts (decorrelator 730 per the claim 1 rejection); and
receiving and combining signals being based on the delayed parts of the frequency representation (the allpass portion of the decorrelator para. 58);
receiving the frequency representation of the audio signal (input to 745);
adjusting an energy of the delayed parts in respect of the frequency representation of the audio signal (stage 745); and
providing a combined shaped frequency representation (output of 755, or 760), when said computer program is run by a computer.
Allowable Subject Matter
Claim 33, rewritten in independent form including all of the limitations of the base claim and any intervening claims, is not disclosed in the prior art of record.
Response to Arguments
The submitted arguments have been considered but are moot in view of the new grounds of rejection.
As per applicant’s argument that the cited delays do not comprise independent delays. The examiner notes the cited subbands are independent signals with independent channels which required independent processing.
Previous responses to previous arguments
As per applicant’s argument that the device in fig. 7 is not a decorrelator, the examiner notes decorrelator stage 730 as cited in the claim 1 rejection.
As per applicant’s argument that Norvell does not teach processing an audio signal but rather decoding a bitstream, the examiner notes the cited prior art, as well as applicant’s claimed device both use decorrelation in the context of a codec (noting applicant’s background specification).
As per applicant’s argument that the disclosure of Norvel does not require or is not related to subbands, the examiner notes the use of the ‘k’ parameter in the context of a dft as per the claim 1 rejection. This is an index to a frequency component/band/subband, each of which require a respective delay stage as part of the decorrelator function per para 58. The examiner further notes the functions in figs 12-18 are described as per multiple subbands para 64-68. Where each subband requires a respective decorrelating allpass/delay stage to function as described in para 50-58..
As per applicant’s argument that Norvell is silent as to forming parts of a frequency representation based on an audio signal, the examiner notes those parts are the cited dft based subbands each separately processed by the decorrelation/allpass/delay processing.
As per applicant’s arguments that Norvell does not disclose that an audio signal forms the basis for the processing including the delayed parts, the examiner notes the system of Norvell is based on an audio input per the abstract.
As per applicant’s argument that Norvell does not disclose different delay units with different frequency representations, the examiner notes those are the cited subbands and their associated decorrelation/allpass/delay process which is respective to each band.
Applicant’s arguments about the spectral/envelope shaping do not take into account the subband based processing as described in the claim rejections above.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXANDER KRZYSTAN whose telephone number is 571-272-7498, and whose email address is alexander.krzystan@uspto.gov
The examiner can usually be reached on m-f 7:30-4:00 est.
If attempts to reach the examiner by telephone or email are unsuccessful, the examiner’s supervisor, Fan Tsang can be reached on (571) 272-7547.
The fax phone numbers for the organization where this application or proceeding is assigned are 571-273-8300 for regular communications and 571-273-8300 for After Final communications.
/ALEXANDER KRZYSTAN/Primary Examiner, Art Unit 2653
Examiner Alexander Krzystan
April 23, 2026
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