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Sample Rate Conversion for Software Radio With respect to the definition of SRC in the introduction to this article, it should be noted that in many cases it is sufficient to preserve the information of one single channel of interest of a multichannel signal when performing SRC on a multichannel signal. Besides the conversion factor, another design parameter is important: the ratio between the sample rate of the signal, and the bandwidth of the channel of interest, that is, the oversampling ratio (OSR) of the channel of interest. This leads to the fact that placing fractional SRC at a high sample rate in a cascaded multirate system would lead to applying another type of filter compared to the type which would be used in case of placing fractional SRC at a low sample rate in the cascade. www.comsoc.org /~ci/private/2000/aug/hentschel.html   (6378 words)

Method for sample rate conversion of digital data - Patent 6313765 In the situation where the two sampling rates are not integer factors of one another a method has been developed to compare the ratios of the two sampling rates and using ratio to analyze each sample number of the bitword in the original data set to determine if sampling of that particular bitword is necessary. The method of converting digital data from a first sampling rate to a second sampling rate of claim 1 wherein the digital data is converted for use in a codec. The method of converting digital data from a first sampling rate to a second sampling rate of claim 4 wherein the digital data is used as part of a voice warning system in a vehicle cockpit. www.freepatentsonline.com /6313765.html   (3401 words)

Sample Rate Conversion   (Site not responding. Last check: 2007-11-02) Sample rate conversion is the process of changing the number of samples taken for every second of audio. It's also clear that if the samples were taken slightly to the left or right we would end up with a similar pattern, but with the samples closer together or quieter, so we still lose some dynamic range when we represent frequencies at the edge of our range. It is impossible for a recording with a low sample rate to include frequencies which are too high for a higher one. www.unrelatedinventions.com /Audiotools/Help/samplerateconversion.htm   (688 words)

U.S. Patent: 6016550 - Method and apparatus for audio sample rate conversion within a data-processing system - January ... If the input sample rate of the audio data stream is not equal to a target sample rate, several frequency multiplications or frequency divisions are selectively performed until the target sample rate is reached. A sample rate conversion algorithm, in accordance with a preferred embodiment of the present invention, may be implemented within sample rate converter 33. Also, the resultant sample rate after any stage must be maintained at a higher rate than the original sample rate (except after the final stage of a sample rate conversion from a higher sample rate to a lower sample rate) so that the maximum frequency content of the original audio data stream reaches the output. www.everypatent.com /comp/pat6016550.html   (3471 words)

CommsDesign - Multi-Rate Processing and Sample Rate Conversion: A Tutorial Sample rate conversion, on the other hand, is employed when resampling a signal at a lower rate in order to allow it to pass through a channel with limited bandwidth. If the receiver can operate at the same sampling rate (or higher), then all that has to be done is to read the received digital signal into the receiver and extract the original signal simply by low pass filtering the signal. The third, and final component, is sampling rate conversion by ratios L and M. This conversion solves the problem of changing sampling rates by a factor that is not an integer. www.commsdesign.com /story/OEG20020222S0071   (2190 words)

Audio File Sample Rate Conversion Sox is used to perform sample rate conversion to 44.1 kHz using each of the sample-rate conversion algorithms. The upper limit of data at an 8 kHz sampling rate is 4 kHz, which is shown by the green line. Sox is used to perform sample rate conversion to 8 kHz using each of the sample-rate conversion algorithms. leute.server.de /wilde/resample.html   (1547 words)

Secret Rabbit Code (aka libsamplerate) One example of where such a thing would be useful is converting audio from the CD sample rate of 44.1kHz to the 48kHz sample rate used by DAT players. SRC is capable of arbitrary and time varying conversions ; from downsampling by a factor of 256 to upsampling by the same factor. SRC provides a small set of converters to allow quality to be traded off against computation cost. www.mega-nerd.com /SRC   (277 words)

z-systems audio engineering - sample rate converters The z-link96 mini sample rate converter is based on the same sample rate conversion technology as the z-3src. The z-link96+ mini sample rate converter is based on the same sample rate conversion technology as the z-3src. Our approach to sample rate conversion is simple: rather than build an expensive synchronous converter based on a custom DSP solution, we use the finest asynchronous sample rate conversion chips*. www.z-sys.com /pp_sample.html   (748 words)

X-Fi - World's Most Powerful Audio Processor The general audio community as a whole has seen sample rate conversion as a necessary evil that should only be used when absolutely necessary. Sample rate conversion plays an important role in digital connectivity, 3D audio modeling, music synthesis and the ability to play and mix multiple sounds recorded at differing sample rates. Despite the transparent sample-rate conversion qualities of X-Fi we recognized that there would still be applications that don't require sample rate conversion of any kind and therefore the flexible routing architecture of X-Fi allows the sample rate conversion to be bypassed when not needed. www.soundblaster.com /products/x-fi/technology/architecture/ssrc.asp   (324 words)

sr-convert sample rate conversion utility Note that regardless of whether the rate comes from the file or from the command line, it must be one of the supported sampling rates. The impulse response is a mathematical function, and it doesn’t have a sampling rate until it is sampled prior to the conversion. But when the sampling rate is very high, there is very little energy in that frequency, and the frequency is very high anyway, so no aliasing is heard. sr-convert.sourceforge.net /sr-convert.html   (3174 words)

Sample rate conversion   (Site not responding. Last check: 2007-11-02) The D-to-A converter produces a piecewise constant (staircase-type) waveform, and by increasing the sampling rate, a better approximation (with smaller steps) to the original analog signal is obtained. For example, the sampling rate for studio work is 48 kHz, whereas that for CD production is 44.1 kHz and the broadcast rate, in turn, is 32 kHz. The obvious way to perform the rate conversion would be to first convert the discrete-time signal into a continuous-time signal and then resample it at the required rate. homes.esat.kuleuven.be /~rombouts/dspII/9   (330 words)

Sample Rate Conversion in Double System Sound - The Digital Video Information Network With audio-for-video using a 48k sample rate but the most common rate with inexpensive recorders being the CD norm of 44.1k, as you point out we need to convert the rate when importing the audio into our project. We could duplicate every 11th sample in the source file or we could look at each pair of samples in the original file and interpolate between them to come up with a "guess-timate" of what that 1 or 2 samples would have been had it been recorded at 48k. Sample rate conversions where the two rates are even integer multiple of each other seem like they would be straight forward and free of introduced distortion - to record in 96k and resample to 48k you'd just drop every alternate sample. www.dvinfo.net /conf/showthread.php?t=56769   (1232 words)

Creative's New X-Fi Audio Processor Previewed at ExtremeTech Sample rate conversion (SRC) is a process by which audio's sampling rate gets changed without affecting the pitch of the audio. However a common SRC task is moving audio between sampling rates of 48 KHz and 44.1 KHz, and this is a task Creative's 10Kx audio processors had trouble with. SRC is a very compute-intensive process, and Creative acknowledged that this operation gated the 10K2.5's audio signal quality performance at 44.1 KHz due to SRC issues. www.extremetech.com /article2/0,1697,1813722,00.asp   (929 words)

Sample Rate Converter   (Site not responding. Last check: 2007-11-02) Sample rate conversion or audio resampling is the process of changing the audio sample rate without affecting the quality. Sample Rate Converter reference design to convert audio signals with different sampling rates into a single synchronous audio stream sampled at 48 kHz. The design can accept audio signals in either AES3/EBU or I2S format and can be targeted to the low-cost Cyclone Altera supplies the Sample Rate Converter core as an encrypted source code and can be configured with easy-to-use intellectual property (IP) toolbench flow. Example designs are provided for demonstrations that run on Altera Stratix GX Video Demonstration Boards. www.altera.com /end-markets/refdesigns/sys-sol/broadcast/ref-sample-rate.html   (349 words)

/home/matthias/java/jsresources/examples/src/SampleRateConverter.java If you want to do sample rate conversion with the Sun jdk1.3/1.4, you have to install Tritonus' sample rate converter. /* Currently, the only known and working sample rate converter for Java Sound requires that the encoding of the source stream is PCM (signed or unsigned). /* Since we now know that we are dealing with PCM, we know that the frame rate is the same as the sample rate. www.jsresources.org /examples/SampleRateConverter.java.html   (426 words)

wavresample -- WAV file sample rate conversion (mex-function) Performs sample rate and/or bit-depth conversion on the input WAV file and saves the results in the output WAV file. Likewise, for multichannel signals, the gain is ineffective when the output scaling is selected as 'normc' since the per-channel normalization eliminates the effect of the gain (though the gains are generally effective in a relative sense when output scaling is set to 'norm'). at half the output sample rate for down-samplers to avoid "aliasing", and at half the input sample rate for up-samplers to avoid "imaging"). www.soundslogical.com /support/mpacks/documentation/english/documentparts/wavresample.html   (1512 words)

FIR Rate Conversion (DSP Blockset) The FIR Rate Conversion block resamples the discrete-time input to a period K/L times the input sample period, where the integer K is specified by the Decimation factor parameter and the integer L is specified by the Interpolation factor parameter. K and L must be relatively prime integers; that is, the ratio K/L cannot be reducible to a ratio of smaller integers. demo compares sample rate conversion performed by the FIR Rate Conversion block with the same conversion performed by a cascade of Upsample, Direct-Form II Transpose Filter, and Downsample blocks. www.cs.berkeley.edu /titan/sww/software/matlab/toolbox/dspblks/firrateconversion.html   (518 words)

diyAudio Forums - Asynchronous Sample Rate Conversion Usually the new samples are evenly spaced between the original samples, in which case we have "integer" interpolation. When a signal is sampled at a rate at least twice the bandwidth of the signal, the information BETWEEN samples is NOT lost... Now in general rate conversion problems, we have BOTH interpolation and decimation to contend with... www.diyaudio.com /forums/showthread.php?s=&threadid=28814   (2182 words)

ReSample Help 5.4--Sample rate conversion Moreover, for computational efficiency, the filters are implemented in multi-stage polyphase form, whereby a given conversion ratio is achieved via a cascade of converters, within each of which the filtering is always carried out at the lower sample rate. The composite (overall) effect of the multiple stages achieves the desired conversion ratio according to the overall lowpass specification in the previous table. Since ReSample also includes a full range of re-quantization and dithering options, the WAV file can be completely re-sampled (in terms of sample rate and bit depth) in a single pass. www.soundslogical.com /support/resample/documentation/english/documentparts/resamplehelp-30.html   (248 words)

diyAudio Forums - Asynchronous Sample Rate Conversion So It would seem to me that as long as the output rate was faster than the input rate (you said earlier that it has to be), the most recent interpolated sample we need would always be between the most recent input sample, and the second most recent input sample. Where by we'd like to add a million samples, equally spaced in both time and amplitude, in between each actual input sample in order to "fill in the gaps". A very accurate way to view interpolation is that the samples generated are essentially the same samples that would have been generated, if you had simply sampled the original analog signal FASTER... www.diyaudio.com /forums/showthread.php?postid=342727   (2724 words)

help with sample rate conversion I have a few mp3 files recorded in either mono or at a sample rate other than 44.1 kz. AudioGrabber wouldn't encode a couple of files that were recorded at different sample rates and a couple that were recored in mono. But I was actually hoping to find a utility that left the file in a mp3 format and striped off the "extra" channel without converting the file to WAV or PCM format thereby removing the file another generation from the original as it gets re-encoded back to mp3 format. forums.afterdawn.com /thread_view.cfm/18367   (502 words)

Sample rate conversion - NI Forums I changed the sample rate in DP 4.12 from 44.1 to 48k. Some samples drop within one second of the note being held down and some will play one time regardless of loop settings. I'm not sure if this bug occurs when you create a project starting with a 96k sample rate, but with a simple insert of the sustain pedal controller matching the lenght of the note, samples will hold and loop properly. www.native-instruments.com /forum/showthread.php?p=82333   (213 words)

KMixer Driver Sample Rate Conversion and Mixing Policy   (Site not responding. Last check: 2007-11-02) This section describes the sample-rate conversion and mixing policy of the KMixer system driver. The streams can be in different wave PCM formats with a variety of sample rates, sample sizes, and channel counts. Samples can be expressed as integer or floating-point values. www.osronline.com /ddkx/stream/aud-design_6tuv.htm   (170 words)

realtime sample rate conversion while recording - Hydrogenaudio Forums to avoid that, the driver system should know which sample rate the software expects and then it should re-sample it to that format. It is an example of a Windows component that can perform the sample rate conversion instead of the driver. none of these items has a configurable interface (property sheet) that is realted to sample rate converion. www.hydrogenaudio.org /forums/index.php?showtopic=19853   (1046 words)

Method and apparatus for sample rate conversion (EP0477131B1) b) When the sample rate is increased, the sampled signal is conducted through such a digital filter that within the frequency range between less than or equal to half the original and half the new sample rate no spectral interference terms occur. Via the requirements for band limiting specified in a and b, the digital filter can be used in both cases, that is to say of reduction and increasing the sample rate, for an even greater band limiting and/or spectral shaping of the signal at the input of the apparatus for sample rate conversion. c) The signal produced is sampled at the new sample rate. www.delphion.com /details?pn=EP00477131B1   (416 words)

BarbaBatch   (Site not responding. Last check: 2007-11-02) To show off the quality of Barbabatch's award winning samplerate conversion algorithm and to make you aware of the fact that there are professional software packages that offer very poor samplerate conversion quality. BarbaBatch performs the conversions to the right in about 7 % of the length of the sound file on an Apple G5 1.8 MHz. The oscillating sweep towards the end might be due to distortion, calculation jitter, rounding errors or a combination. www.audioease.com /Pages/BarbaBatch4/Barba4SRCTest.html   (630 words)

Bug ID: 4916960 RFE: sample rate conversion should be supported for explicit conversions, too RFE: sample rate conversion should be supported for explicit conversion, tooWhile sample rate conversion is supported internally for SourceDataLines, it is not supported generally for AudioInputStreams. It should be possible to request a sample rate conversion via AudioSystem.getAudioInputStream(AudioFormat, AudioInputStream). This requires that the code doing sample rate conversion is made available via a FormatConversionProvider. bugs.sun.com /bugdatabase/view_bug.do?bug_id=4916960   (146 words)

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