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various in .NET Develop qr-codes in .NET various

various using .net vs 2010 toget qrcode in asp.net web,windows application Developing with Visual Studio .NET 10 Mbps 34.3.1 Contin uous-pulse UWB Technology Pulse UWB wherein the bandwidth is the reciprocal of the pulse duration can be implemented as a continuous sequence of pulses sent at a rate equal to the pulse bandwidth.

This results in Continuous-pulse UWB (C-UWB) sent at a very high chip rate. One implementation, capable of data rates as high as 2.7 Gbps in a 1.

4 GHz bandwidth, is CWaveTM technology from Pulse~Link. Another, low data rate implementation, is described in the IEEE 802.15.

4a specification [9]. In C-UWB the baseband reference pulse has nominal chip duration of Tc which normally ranges from 0.5 to 2 ns producing bandwidths between 2 GHz and 500 MHz respectively.

The baseband reference pulse spectrum for the complete transmission system including a matched filter receiver is defined by. Ultra-Wideband Wireless Technology 727 T X(f )= c 2 Tc Tc 1 + cos 0 1 f 2Tc for for for 0 f . 1 2Tc 1 1+ f 2Tc 2Tc 1+ f 2Tc where f is th e frequency, Tc is the pulse duration, and is the roll-off factor which is typically between 0.3 and 0.7.

The transmitter reference pulse may be defined in the time domain as the impulse response of the root raised cosine filter, the square root of the filter spectrum described above, and is. t (1 + qrcode for .NET ) Tc t (1 ) + cos 4 t sin Tc Tc 4 r (t ) = 4t 2 Tc 1 Tc . The transmitt ed pulse shape pTX(t) is constrained by the shape of its cross correlation function with a standard reference pulse r(t). For the purposes of testing a transmitter pulse for compliance we define the cross correlation X( ) of the transmitter pulse pTX(t) with r(t) as. X ( ) =. 1 r (t ) pTX (t + )dt PTX R where PTX is .net framework QR-Code the energy in the transmitter pulse found from the time integral of the square of pTX(t), and R is the energy in the reference pulse found from the time integral of the square of r(t). The cross correlation X( ) for a compliant transmitter is greater than 0.

7071 for a continuous range of surrounding the peak cross correlation value, and the range of should be equal to at least 26% of the reference pulse width. In addition, the remaining side-lobes of the correlation function should be less than or equal to 0.3.

While the measurement described here occurs on the pulse envelope as if shaping is done at baseband, it is not intended or implied that pulse shaping occurs only at baseband. Conceptually, the reference pulse is translated to the operating frequency by multiplication with cos(2 ft) and by sin(2 ft) to obtain two essentially orthogonal pulses rI(t) and rQ(t). In practice, filtering techniques and direct pulse synthesis may be used.

Either of the pulses can be polarity modulated in a fashion analogous to BPSK in conventional radio. Both pulses rI(t) and rQ(t) can each be independently polarity modulated with the signals added together to form a 4-level encoding scheme analogous to QPSK in conventional radio. Signal generation and modulation, as well as other UWB pulse designs are further described in [2], [11], [9].

. 728 Ultra-Wideband Wireless Technology 34.3.2 CWaveT .

net framework QR Code M UWB Technology CWaveTM is a continuous pulse or C-UWB technology using 0.741 ns long pulses sent at a 1.35 GHz rate to implement a high data rate communication system.

The pulses are defined by Equations (2) (4) with =0.3 and are polarity modulated. Golay spreading codes in combination with low density parity code (LDPC) forward error correction are employed to achieve a range of data rates from 20 to 1350 Mbps.

The use of two orthogonal pulses enables a doubling of the data rates in the same RF bandwidth to 2700 Mbps. The technology has been successfully demonstrated by transmission between UWB antennas as well as over home CATV networks where it is suitable for transporting IEEE 1394 signaling at application layer throughput rates of more than 400 Mbps with simple polarity modulation and up to 800 Mbps with orthogonal signaling. The top-level description is shown in Figure 34.

3. In the transmitter, the PHY protocol data unit (PPDU) elements are scrambled, encoded, spread and formatted, then mapped into symbols and modulated onto the final waveform for transmission over the cable system. Upon reception, the waveform is demodulated, and the chip stream is de-spread, decoded and de-scrambled for presentation to the MAC.

Dataflow in the transmitter and receiver are illustrated by Figure 34.3. A chip (or pulse) is the fundamental PHY signaling unit and is transmitted at a fixed rate of 1.

35 Gcps for either one pulse shape or a parallel pair of orthogonal pulses. Parallel sequences of chips using orthogonal UWB pulses double the combined chip rate to 2.7 Gcps.

The information content of a sequence of chip varies according to the FEC rate, the spread factor, and pulse orthogonality. Referring to Figure 34.3, the Data Input bit stream is first scrambled, then forward error correction (FEC) using Low Density Parity Check (LDPC) algorithm is applied to the scrambled bits.

The number of output bits (coded bits) equals the inverse of the FEC rate, thus a rate 0.5 FEC doubles the number of transmitted bits. This encoded bit stream is then spread by the spreading code sequence factor of 1, 2, 4, 8, or 64.

Spreading is the dotmultiplication of each coded bit by a contiguous set of chips chosen based on a given spreading code sequence. The ratio of the symbol duration in time to the chip duration in time is the processing gain..

Data input Sc rambler LDPC encoder Spreader (symbol encode) Preamble generator Pulse shaper (modulation) UWB transmitter RF channel Data output Descrambler LDPC Decoder De-spreader (symbol decode) Synchronizer from preamble Pulse detector (demodulation) UWB receiver.
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