Digital Communication Record
Author: Nan Wang
Particular date: 15/05/2013
1 . Introduction
At present, the raising interest in convenient communication offers heightened the advantages of digital connection development. This kind of report could introduce a great ambulance support system. Because an emergency program, it should be speedy response; additionally , the quality of the signal indication is also very important. Then it is essential to choose the ideal components.
Graph 1 
1 . Digital source
Generally, the graph shows above is a general block plan of a digital communication system. Furthermore, this system should be inside the environment of Ultra High Frequency which rate of recurrence should between 300-3000 MEGAHERTZ. To be more specific, the digital source in this model comes with 3 types of data: the first one is the digitized ‘telephone quality' voice the voice sign, the various other two are definitely the imagine transmission, one is from the patient monitor and the additional one is from your digital camera. In addition , the monitoring system will produce a lot of binary data like blood pressure data. Then the system needs to be specific like this:
1 . 1 Parameter Calculations
Through the task requirement, the speed of secours v=120km/h=33. 3m/s, frequency f=2 GHZ, bandwidth B=10 KHZ, Signal Sound Ratio SNR=50dB. Then we're able to calculate Doppler shift: =222. 2 HZ. This Doppler shift would have some romance with the interleaver length which in turn would be utilized in channel code, and the monitoring system will produces data at a fixed rate of 100 bps. In this state, based on the Simulink of interleaving we could estimate once interleaver around 150*150, the small amount error rate is the most affordable. Then depending on Shannon theory, we could estimate the max transmission info rate:, S/N here is the Sign Noise Proportion which symbolize in die bahn. Therefore , you ought to converter the 50dB in a specific amount, due to, S/N should be 10^5 here. After that Rmax=166kbps. Even so 28. 8kbps is the limit of modulator, then if SNR wasn't able to be increased or without appropriate origin coding, modulator could not meet higher info rate. Finally, we could determine Eb/No utilizing the data price and bandwidth, the maximum Eb/No=SNR*B/C=37. 79dB. 2 . Source code
As we know, the voice and picture signal may change into a consistent analog transmission like current or volt quality. Therefore , you ought to use an analog digital ripping tools here in in an attempt to communication in a digital method. The next is definitely the source coding, it is must be noticed that source coding differs with the route coding. The real key to supply coding should be to reduce the size of the information in order to convenient transmitting and match to ideal bandwidth. The aim of the source coding is utilize smallest size of data to transmit one of the most information. Currently, in television set area, the most frequent source coding is the MPEG-2, which could give both tone source coding and online video source coding. As the end result, it could be a desirable source coding in this system. 3. Channel coding
After that, it is important to discuss the channel coding. Channel coding can be used for improving the quality of data transmission.  The main theory of funnel coding is to add some checking bits within a rule. At the same time the obtaining end would detect the errors also correct the errors. several. 1 Hamming Code
Firstly it is necessary to described Hamming Code. As mentioned in the worksheet Hamming Code can be an error fixing binary code, it can discover 1 little bit and a couple of bits problems but can simply correct 1 bit error. For example , like (7, 4) Hamming Code, it added 3 checking bits in to 4 info bits. Furthermore, the...