Visual Studio .NET qr code iso/iec18004 integrating in .net
using vs .net todisplay qr on asp.net web,windows application
y(n) Framer LSP quantizer Simulated decoder LSP decoder LSP interpolator
decode quick response code with .net
Using Barcode decoder for .NET Control to read, scan read, scan image in .NET applications.
Highpass filter
Barcode implement on .net
using .net framework tomake bar code in asp.net web,windows application
~ Am(z) Wm(z) Impulse response calculator Pm(z) Hm(z) Memory update eu,m(n) Pitch prediction decoder Lopt,m, bopt,m em(n) ev,m(n)
Barcode decoder with .net
Using Barcode scanner for .net vs 2010 Control to read, scan read, scan image in .net vs 2010 applications.
Control qr image for c#.net
use .net vs 2010 qr code 2d barcode integration toget qr code 2d barcode on .net c#
QR encoding on .net
using aspx.cs page todevelop qr-code with asp.net web,windows application
LPC analysis
Control quick response code image on vb
generate, create quick response code none with vb.net projects
Ean13 development with .net
using visual .net crystal toembed european article number 13 on asp.net web,windows application
Zero input response zm(n)
.net Framework Crystal data matrix encoding on .net
using .net framework crystal tomake 2d data matrix barcode with asp.net web,windows application
Secondary excitation decoder
Incoporate ucc-128 in .net
using .net framework toencode ucc - 12 with asp.net web,windows application
Formant perceptual weighting fm(n) Pitch estimator
Build bar code for .net
using visual .net crystal toget bar code on asp.net web,windows application
Harmonic noise shaping
Visual .net Crystal usd-3 maker with .net
using visual studio .net crystal touse code 93 full ascii for asp.net web,windows application
Pitch predictor vm(n)
Control barcode 128 data with java
to render code128b and code 128a data, size, image with java barcode sdk
UPC - 13 barcode library in .net
using barcode integrated for rdlc report control to generate, create ean13+2 image in rdlc report applications.
Control ucc-128 data for visual c#.net
gs1-128 data on visual c#.net
Control universal product code version a data with visual basic.net
to integrate upc a and upc a data, size, image with vb barcode sdk
Figure 11.5 Block diagram of G.723.1 CODEC
Control upca data in .net
gtin - 12 data with .net
Calculating the LPC coef cients requires the past, current, and future subframes. The LPC synthesis lter is de ned as 1 = Am (z) 1 1
Bar Code integrating on .net
using .net winforms todraw bar code for asp.net web,windows application
10 i=1
Control 3 of 9 barcode data for visual c#
to generate code 39 full ascii and code 39 data, size, image with visual c# barcode sdk
Control ean / ucc - 14 size on microsoft excel
to encode ean/ucc 128 and ean128 data, size, image with excel barcode sdk
ai,m z i
where m = 0, 1, 2, 3 is the subframe index. As shown in Figure 11.5, the LPC lter coef cients of the last subframe are converted to LSP (line spectral pairs) coef cients. The reason for doing LPC to
180-sample LPC analysis windows
Past 60
Subframe2 Subframe3 240
Look-ahead 60
G.723.1 LPC analysis windows vs. subframes
Table 11.4 Seq. 1 2 3 4 5 Computed parameters
Procedures of LPC coef cient calculation and reconstruction Subframe 0 {ai,0 } Subframe 1 {ai,1 } Subframe 2 {ai,2 } Subframe 3 {ai,3 } { i,3 } { i,3 } { i,3 } {ai,3 }
LPC coef cients LSP coef cients LSP coef cients quantization and dequantization Interpolated LSP coef cients Reconstructed LPC coef cients
{ i,0 } {ai,0 }
{ i,1 } {ai,1 }
{ i,2 } {ai,2 }
LSP coef cients conversion is to take the advantages of two properties of LSP coef cients: to verify the stability of the lter and to have higher coef cients correlation among subframes. The rst property can be used to make synthesis lter stable after quantization, and the second is used to further remove redundancy. The LPC coef cients calculation and quantization can be further explained with Table 11.4 and the following procedures:
1. Compute {ai,m } for subframes m = 0, 1, 2, 3 and 10th-order LPC coef cients i = 1, . . . , 10. With {ai,m }, we can construct Equation (11.21). The unquantized LPC coef cients are used to construct the short-term perceptual weighting lter Wm (z), which will be used to lter the entire frame to obtain the perceptually weighted speech signal. 2. Convert the last subframe s {ai,3 } to LSP coef cients { i,3 }. 3. Use vector quantization to quantize the 10 LSP coef cients into LSP index for transmitting. Dequan tize the LSP coef cients to { i,3 }. 4. Use the LSP coef cients { i,3 } from the current frame and the last frame to interpolate the LSP coef cients for each subframe { i,m }. 5. Convert LSP coef cients { i,m } back to LPC coef cients {ai,m } and construct the synthesis lter m (z) for each subframe. Note that even in the encoder side, we also need this in order for both 1/ A sides to use the same set of synthesis lter. Decoding side never has the unquantized LPC coef cients.
The pitch estimation is performed on two adjacent subframes of 120 samples. The pitch period is searched in the range from 18 to 142 samples. Using the estimated open-loop pitch period L olp,m , a harmonic noise-shaping lter Pm (z) can be constructed. The combination of the LPC synthesis lter with the formant perceptual weighting lter and the harmonic noise-shaping lter, Hm (z) = Wm (z) Pm (z) / Am (z), is used to create an impulse response h m (n)(n = 0, . . . , 59). The adaptive excitation signals ev,m (n) and the secondary excitation signal eu,m (n) are ltered by this combined lter to provide the zero-state responses u m (n) and vm (n), respectively. In adaptive codebook excitation, a fth-order pitch predictor is used. The optimum pitch periods (L opt,m ) of subframe 0 and 2 are computed via closed-loop vector quantization around the open-loop pitch estimate L olp,m . The optimum pitch periods in subframes 1 and 3 are searched for differential values around the previous optimum pitch periods of subframes 0 and 2, respectively. The pitch periods of subframes 0 and 2, and the differential values for subframes 1 and 3 are transmitted to the decoder.