bộ thu phát không dây e wr750

Ngày tải lên: 13/07/2014, 17:35

Ngày tải lên: 24/12/2013, 11:16

Ngày tải lên: 24/12/2013, 11:16

Ngày tải lên: 24/12/2013, 11:16

Ngày tải lên: 24/12/2013, 11:16

Ngày tải lên: 24/12/2013, 11:16

... average BERs. When the average SNR is over 25dB and the target average BEP is low, the average BEP of the AQAM scheme begins to decrease, preventing the scheme from increasing the average ... adaptive schemes and fixed schemes increases, as the tar- get BEP decreases. It is interesting to note that the average BPS curves of the adaptive PSK schemes seem to converge to a set of densely ... fixed PSK schemes are represented as various types of lines with mark- ers according to the key legend shown in Figure 6.23. We can observe that the difference between the required SNRs of the...

Ngày tải lên: 21/01/2014, 17:20

... the reference user was dependent on the data estimates of the interferer. Consequently, this inter-dependency severely degraded the performance of the JD-"SE-BDFE receiver. The higher-order ... degraded due to insufficient information regarding the interferer. Consequently, the performance of the JD-MMSE-BDFE receiver was severely affected, since the data esti- mation of the reference ... the reference user are listed in Table 7.1. receiver, since any errors corrupted the data estimation of both the reference user and the in- terferer. This was detrimental, since the data estimation...

Ngày tải lên: 21/01/2014, 17:20

... Furthermore, the a posferjori probabilities generated can be used to directly estimate the associated BER without any reference signal. The BER estimate can be used by the receiver as a measure ... Noise-free Channel Output States In this section, we will describe in detail the scalar noise-free channel output states and relate them to the m-element noise-free channel output state vector ... thesis. 8.1 Discrete Time Model for Channels Exhibiting Intersymbol Interference A band-limited channel that results in intersymbol interference (ISI) can be represented by a discrete-time...

Ngày tải lên: 21/01/2014, 17:20

... transmission frequency bands are different. Explicitly, the receiver has to instruct the remote transmitter concerning the modem mode to be used for meeting the receiver’s target integrity requirements. ... the context of the High-BER candidate scheme and in conjunction with the near-error-free schemes. However, the performance gains of the High-BER schemes were less than those of the Low-BER ... the expense of increased computational complexity. However, the present parameter values for the conventional DFE and RBF DFE are convenient, since they yield similar BER performances. The...

Ngày tải lên: 21/01/2014, 17:20

... the conventional DFE were a feedforward order of 7 and feedback order of 1, which were assigned such that they gave the best possible BER performance according to our experiments and hence ... magnitude. Increasing the number of decoder iterations improves not only the BER, but also the average confidence measure of the decoder’s decisions. Figure 10.13 shows the relationship between ... any reduction of the BPS throughput, and hence this switching metric was deemed more beneficial to invoke. This is because due to the higher steepness of the turbo-decoded BER curve, the BER...

Ngày tải lên: 21/01/2014, 17:20

... iteration gain was defined as the difference between the channel SNR required in order to achieve a certain BER after one iteration and the corresponding channel SNR required after n number ... turbo equaliser exhibited a performance that was close to that achievable over non-dispersive channels, despite the presence of Inter- Symbol Interference (ISI), when performing the channel equalization ... achieved. However, in practice these estimates have to be generated at the receiver. namely r’~(t) and T’Q (t), respectively, can be viewed as the result of convolving both quadra- ture components...

Ngày tải lên: 21/01/2014, 17:20

... Multiuser Detection In all the multiuser receiver schemes discussed earlier, the required parameters - except for the transmitted data estimates - were assumed to be known at the receiver. ... the despreading filters was matched to the desired spreading sequence, while the other despreading sequences were ar- bitrarily chosen such that the impulse responses of the filters were ... ending with the weakest signal. For each user, the interference inflicted by the other users was regenerated using the estimates of the current stage for the stronger users and the estimates...

Ngày tải lên: 21/01/2014, 17:20

... parameters has to be communicated to the receiver in order to successfully demodulate and decode the OFDM symbol. If the receiver itself determines the requested parameter set to be used by ... system in the absence of interference is an example of such a system, and hence a TDD regime is assumed for generating the performance results below. Channel reciprocity issues were addressed, ... where different modulation schemes suffer to different extents from the effects of the channel transfer func- tion. Coherent modulation schemes rely on the knowledge of the symbols’ reference...

Ngày tải lên: 21/01/2014, 17:20

... From the figure we can also see that the performance gain of the concatenated Gz/TC(2,1,3) channel coded scheme over the space-time trellis codes becomes lower, when the number of receivers is ... basis of the coding gain defined as the &/No difference, expressed in decibels, at a FER= between the schemes investigated and the uncoded single-transmitter, single-receiver system having ... be employed, in order to increase the throughput of the system. However, as we increase the number of receivers, i .e. the diversity order, we observe that the variation of the channel becomes...

Ngày tải lên: 21/01/2014, 17:20

... the average SNR increases. On the other hand, the relative SNR advantage of adaptive schemes in comparison to fixed-mode schemes increased as the target average BER became lower and decreased ... constituted an upper bound estimate, since perfect channel estimation of the reference user and the interferer was assumed. The concept of segmented wideband AQAM was then introduced, in order to reduce ... observed in the context of the High-BER candidate scheme and in conjunction with the near-error-free schemes. However, the performance gains of the High-BER schemes were less than those of the...

Ngày tải lên: 21/01/2014, 17:20

... các hàm receiver.available(), receiver.read(), receiver.rxPL() và Serial.print(): if(receiver.available()) //nếu sẵn sàng nhận giá trị thì khởi chạy hàm nhận { { receiver.read(); // đọc ... truyền phát không dây Trang 32 receiver.channel(90); receiver.RXaddress("Artur"); receiver.init(); Serial.print("Led nhap nhay canh bao khi T* > "); Serial.print(Wtemp); ... giá trị nhận receiver.rxPL(temp); //nhận giá trị receiver.rxPL(tempF); Serial.println("Nhiet do da nhan: "); //hiển thị lên Serial Monitor Serial.print(temp); Serial.println("...

Ngày tải lên: 21/06/2014, 14:33

... bởi một bộ thu, phát. Hai trường SENDER_ID và RECEIVER_ID trong khung chỉ thị dùng để chỉ ID nút chứ không phải ID của bộ thu, phát. Byte cuối cùng là FRAME_TYPE chỉ ra sự tham gia của máy phát ... giữa hai bộ thu, phát (cm) θ Góc chiếu của một bộ thu, phát (Rad) φ Góc giữa hai bộ thu, phát liền kề (Rad) L Vùng phủ của một bộ thu, phát (cm 2 ) C Vùng phủ hiệu dụng của một bộ thu, phát (cm 2 ) I ... dài 4 byte), do đó một khung sẽ không giữ kênh vật lý bận quá lâu. Cấu trúc khung bao gồm 4 trường: FRAME_START, SENDER_ID, RECEIVER_ID và FRAME_TYPE. Trường FRAME_START có độ dài 1 byte dùng để...

Ngày tải lên: 21/06/2014, 17:46

Ngày tải lên: 11/07/2014, 21:20

Ngày tải lên: 13/07/2014, 21:20