orginal seminae cellonics seminar report

Seminar report 2013

CHAPTER 1 INTRODUCTION Are you tired of slow modem connections? Cellonics Incorporated has developed new technology that may end this and other communications problems forever. The new modulation and demodulation technology is called Cellonics. In general, this technology will allow for modem speeds that are 1,000 times faster than our present modems. The development is based on the way biological cells communicate with each other and nonlinear dynamical systems (NDS). Major telcos, which are telecommunications companies, will benefit from the incredible incr edible speed, simplicity, and robustness of this new technology, as well as individual users. In current technology, the ASCII uses a combination of ones and zeros to display a single letter of the alphabet (Cellonics, 2001). Then the data is sent over radio frequency cycle to its destination where it is then decoded. The original technology also utilizes carrier signals as a reference which uses hundreds of wave cycles before a decoder can decide on the bit value (Legard, 2001), whether the bit is a one or a zero, in order to translate that into a single character. The Cellonics technology came about after studying biological cell behaviour. The study showed that human cells respond to stimuli and generate waveforms that consist of a continuous line of pulses separated by periods of silence. The Cellonics technology found a way to mimic these pulse signals and apply them to the communications industry (Legard, 2001). The Cellonics element accepts slow analog waveforms as input and in return produces predictable, fast pulse output, thus encoding digital information and sending it over communication channels. Nonlinear Dynamical Systems (NDS) are the mathematical formulations required to simulate the cell responses and were used in building Cellonics. Because the technique is nonlinear, performance can exceed the norm, but at the same time, implementation is straightforward (Legard, 2001).

DEPT of Electronics and communication communicati on

1

MESITAM Chathannoor

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Seminar report 2013

CHAPTER 2 BIRTH OF CELLONICS For the last 60 years, the way radio receivers are designed and built has undergone amazingly little change. Much of current approach could be attributed to EH Armstrong, the oft -credited Father of FM, who invented the super heterodyne method in 1918.He further developed it into a complete FM commercial system in 1933 for use in public-radio broadcasting. Today, more than 98% of receivers in radios, television televisi on and mobile phones use this method.The subsystem used in the superhet design consists of radio-frequency (RF)amplifiers mixers ,phase-lock loops ,filters, oscillators and other components ,which are all complex ,noisy ,and power hungry. Capturing a communications element from the air to retrieve its modulated signal is not easy ,and a system often needs to spend thousands of carrier cycles to recover just one bit of information .This process of demodulation is inefficient ,and newly emerging schemes result in complex chips difficult and expensive to manufacture.So it was necessary to invent a new demodulation circuit ,which do the job of conventional superheterodyne receiver but at a far lesser component count, faster and lower in power consumption and possessing greater signal robustness These requirements were met by designing a circuit which models the biological cell behavior as explained earlier. The technology for this, named CELLONICS ,was invented by scientists from CWC(Censer for Wireless communication) and Computational Science Department in Singapore.















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CHAPTER 3 CONVENTIONOL RECIEVER In electronics, a superheterodyne receiver (often shortened to superhet) uses frequency mixing or heterodyning to convert a received signal to a fixed intermediate frequency (IF), which can be more conveniently processed than the original radio carrier frequency. Virtually all modern radio receivers use the superheterodyne principle

Fig1.1 super hetroyne reciever

Superheterodyne" is a contraction of "Supersonic Heterodyne", where "supersonic" indicates frequencies above the range of human hearing. The word heterodyne is derived from the Greek roots hetero- "different", and -dyne "power". In radio applications the term derives from the "heterodyne detector" pioneered by Canadian inventor Reginald Fessenden in 1905, describing his proposed method of producing an audible signal from the Morse Code transmissions of an Alexanderson alternator-type transmitter. With the spark gap transmitters then in use, the Morse Code signal consisted of short bursts of a heavily modulated carrier wave which could be clearly heard as a series of short chirps or buzzes in the receiver's headphones. However, the signal from an Alexanderson Alternator did not have any such inherent modulation and Morse Code from one of those would only be heard as a series of















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beat together to produce a 3 kHz tone thus in the headphones the morse signals would then be heard as a series of 3 kHz beeps. For this he coined the term "heterodyne" meaning "Generated by a Difference" (in frequency). The superheterodyne principle was devised in 1918 by U.S. Army Major Edwin Armstrong in France during World War I.[1][2] He invented this receiver as a means of overcoming the deficiencies of early vacuum tube triodes used as high-frequency amplifiers in radio direction finding equipment. Unlike simple radio communication, which only needs to make transmitted signals audible, direction-finders measure the received signal strength, which necessitates linear amplification of the actual carrier wave. In a triode radio-frequency (RF) amplifier, if both the plate (anode) and grid are connected to resonant circuits tuned to the same frequency, stray capacitive coupling between the grid and the plate will cause the amplifier to go into oscillation if the stage gain is much more than unity. In early designs, dozens (in some cases over 100) low-gain triode stages had to be connected in cascade to make workable equipment, which drew enormous amounts of power in operation and required a team of maintenance engineers. The strategic value was so high, however, that the British Admiralty felt the high cost was justified. Armstrong realized that if radio direction-finding (RDF) receivers could be operated at a higher frequency, this would allow better detection of enemy shipping. However, at that time, no practical "short wave" (defined then as any frequency above 500 kHz) amplifier existed, due to the limitations of existing triodes. It had been noticed some time before that if a regenerative receiver was allowed to go into oscillation, other receivers nearby would suddenly start picking up stations on frequencies different from those that the stations were actually transmitted on. Armstrong (and others) eventually deduced that this was caused by a "supersonic heterodyne" between the station's carrier frequency and the oscillator frequency. Thus if a station was transmitting on 300 kHz and the oscillating receiver was set to 400 kHz, the station would be heard not only at the original 300 kHz, but also at 100 kHz and 700 kHz. Armstrong realized that this was a potential solution to the "short wave" amplification problem, since the beat frequency still retained its original modulation, but on a lower carrier frequency. To monitor a frequency of 1500 kHz for example, he could set up an oscillator at, for example, 1560 kHz, which would produce a heterodyne difference frequency of 60 kHz, a















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In December 1919, Major E. H. Armstrong gave publicity to an indirect method of obtaining short-wave amplification, called the super-heterodyne. The idea is to reduce the incoming frequency which may be, say 1,500,000 cycles (200 meters), to some suitable super-audible frequency which can be amplified efficiently, then passing this current through a radio frequency amplifier and finally rectifying and carrying on to one or two stages of audio frequency amplification.[3] Early superheterodyne receivers used IFs as low as 20 kHz, often based on the self-resonance of iron-cored transformers. This made them extremely susceptible to image frequency interference, but at the time, the main objective was sensitivity rather than selectivity. Using this technique, a small number of triodes could be made to do the work that formerly required dozens of triodes. In the 1920s, commercial IF filters looked very similar to 1920s audio interstage coupling transformers, had very similar construction and were wired up in an almost identical manner, and so they were referred to as "IF Transformers". By the mid-1930s howevaer, superheterodynes were using much higher intermediate frequencies, (typically around 440 – 440 – 470 kHz), with tuned coils similar in construction to the aerial and oscillator coils. However, the name "IF Transformer" was retained and is still used today. Modern receivers typically use a mixture of ceramic resonator or SAW (surface-acoustic wave) resonators as well as traditional tuned-inductor IF transformers. Armstrong was able to rapidly put his ideas into practice, and the technique was rapidly adopted by the military. However, it was less popular when commercial radio broadcasting began in the 1920s, mostly due to the need for an extra tube (for the oscillator), the generally higher cost of the receiver, and the level of technical skill required to operate it. For early domestic radios, tuned radio frequency receivers ("TRF"), also called the Neutrodyne, were more popular because they were cheaper, easier for a non-technical owner to use, and less costly to operate. Armstrong eventually sold his superheterodyne patent to Westinghouse, who then sold it to RCA, the latter monopolizing the market for superheterodyne receivers until 1930.[4] By the 1930s, improvements in vacuum tube technology rapidly eroded the TRF receiver's cost advantages, and the explosion in the number of broadcasting stations created a demand for cheaper, higher-performance receivers.















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for superheterodyne operation, most notably the pentagrid converter. By reducing the tube count, this further reduced the advantage of preceding receiver designs.

By the mid-1930s, commercial production of TRF receivers was largely replaced by superheterodyne receivers. The superheterodyne principle was eventually taken up for virtually all commercial radio and TV designs .The principle of operation of the superheterodyne receiver depends on the use of heterodyning or frequency or frequency mixing. The signal from the antenna is filtered sufficiently at least to reject the image frequency and possibly amplified. A local oscillator in the receiver produces a sine wave which mixes with that signal, shifting it to a specific intermediate frequency (IF), usually a lower frequency. The IF signal is itself filtered and amplified and possibly processed in additional ways. The demodulator uses the IF signal rather than the original radio frequency to recreate a copy of the original information (such as audio). To receive a radio signal, a suitable antenna is required. This is often built into a receiver, especially in the case of AM broadcast band radios. The output of the antenna may be very small, often only a few microvolts. The signal from the antenna is tuned and may be amplified in a so-called radio frequency (RF) amplifier, although this stage is often omitted. One or more tuned circuits at this stage block frequencies which are far removed from the intended reception frequency. In order to tune the receiver to a particular station, the frequency of the local oscillator is controlled by the tuning knob (for instance). Tuning of the [6]

local oscillator and the RF stage may use a variable capacitor, or varicap diode. diode.

The tuning

of one (or more) tuned circuits in the RF stage must track the tuning of the local oscillator

















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CHAPTER4 PRINCIPLE OF CELLONICS TECHNOLOGY















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communications, the technology has the ability to encode, transmit and decode digital information powerfully over a variety of physical channels, be they cables or wirelessly through the air. There have been much research over the past decades to study inter-cell communications. Laboratory studies have recorded electrical waveforms that show burst of spikes separated by periods of silence

Fig 4.2.Leech cell response

For examples, Fig 1 and Fig 2 show the behaviour of the ß-cell and the Leech Nociceptor respectively. From these figures, we may observe that the slow waveforms2 trigger the fast pulse trains3 allowing the cells to convey information (as postulated by some researchers).Note that while the fast pulse trains are always the same, the slow time-varying















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as communications and electronic circuits (gated oscillator, sigma delta modulator, delta modulator, clock multipliers, etc). When applied in communications, the Cellonics™ technology is a fundamental modulation and demodulation technique. The Ce llonics™ receivers are used as devices that generate pulses from the received analog signal and perform demodulation based on pulse pulse counting and related algorithms. 1 The study of biological cell behaviour is only an inspiration to the invention of Cellon ics™ circuits. The Cellonics technology is not related to any neural network communications or neurophomic electronics. 2 Slow waveforms: Analogue waveforms that vary slowly with time. These waveforms can be in any arbitrary shape. 3 Fast waveforms/fast pulse trains: Waveform in the shape of pulses that varies rapidl y with time.















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CHAPTER 5 THE CELLONICS CIRCUITS

There are two types of cellonic circuits 1 S curve circuits 2N curve circuits 5.1 S curve cellonics circuits

Cellonics Inc. has developed and patented families of Cellonics™ circuits that are useful for various applications. One of these Cellonics™ circuits is an extremely simple circuit that exhibits the “Scurve” transfer characteristic. Fig 3a shows one of the possible c ircuit realizations. The circuit contains a negative impedance converter. Its iv transfer characteristic is shown in Fig 3b.Thetransfer characteristic consists of three different regions. The two lines at the top and bottom have positive slope, 1/RF and they represent the regions in which the Op-Amp is operating in the saturated (nonlinear) mode. In Fig 3b, the middle segment has a negative slope (negative resistance)















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Fig 5.2: Phase Space & I-V Characteristics Characteristics Curve

and represents the region in which the Op-Amp is operating linearly. It is this negative resistance region that allows the Op-Amp to oscillate and produce pulses bounded by the positive and negative saturation voltages.

For ease of explanation4, we assume that the input signal is a triangular waveform. Here we have dVs/dt = (V0 depending on the slope of the triangular input waveform. Whenever the slope is positive, the Op-Amp is stable and outputs a constant saturation voltage. Thus a silent period is observed i.e. no spike is being produced. On the other hand, with properly

















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5.2 N curve curve circuits

By using the Principle of Duality, the “N -curve” families of Cellonics™ circuits can be derived. In this case, the realization of the circuits can be based on the OP-AMP or devices such as he tunnel diode, etc. The transfer function of a tunnel diode exhibits the “N - curve” transfer characteristic inherently, which is a “dual” of the SS -curve” family. By connecting an inductor and a tunnel diode in series, we can produce pulses that are separated by periods of silence. This family of circuits responds to the voltage level of the input signal. As an application example, a square wave signal is used in Fig 3d. In this case, the duration when the input signal is above a certain “threshold” voltage determines the duration that the circuit operates in the unstable region and consequently the number of pulses generated















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The tunnel diode s basically a pn junction with heavy doping of p type and n type semiconductor materials .tunnel diode is doped 1000 times as heavily as a conventional diode Heavy doping results in large no of majority carriers. Because this large no of carriers, most are not used during initial recombination that produces depletion layer. It is very narrow. Depletion layer of tunnel diode is 100 times narrower. Operation of tunnel diode depend son the tunneling effect Tunneling

The movement of valence electrons from the valence energy band to the conduction band with little or no applied forward voltage voltage is called tunneling.















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Fig 5.4.Energy band diagram of tunnel diode















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As the forward voltage is first increased, the tunnel diode is increased from zero, electrons from the n region tunnel through the potential barrier to the potential barrier to the p region. As the forward voltage increases the diode current also increases until the peak to peak is reached. Ip = 2.2 mA. Peak point point voltage =0.07V As the voltage is increased beyond Vp the tunneling action starts decreasing and the diode current decreases as the forward voltage is increased until valley point V is reached at valley point voltage Vv= 0.7V between Vand P the diode exhibits negative resistance i.e., as the forward bias is increased , the current decreases. When operated in the negative region used as oscillator.

Tunnel diode is a type of sc diode which is capable of very fast and in microwave frequency range. It was the quantum mechanical effect which is known as tunneling. It is ideal for fast oscillators and receivers for its negative slope characteristics. But it cannot be used in large integrated circuits – that‟s why it‟s an applications are limited. When the voltage is first applied current stars flowing through it. The current increases with the increase of voltage. Once the voltage rises high enough suddenly the current again starts increasing and tunnel diode stars behaving like a normal diode. Because of this unusual behavior, it can be used in















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stable oscillator circuit when they are coupled to a tuned circuit or cavity, biased at the centre point of negative resistance region. Here is an example of tunnel diode diode oscillatory circuit. The tunnel diode is losing coupled to a tunable cavity. By using a short, antenna feed probe placed in the cavity off centre loose coupling is achieved. To increase the stability of oscillation and achieve o/p power over wider bandwidth loose coupling is used. The range of the output power produced is few hundred microwatts. This is useful for many microwave application. The physical position of the tuner determining the frequency of operation. If the frequency of operation is changed by this method, that is called mechanical tuning. Tunnel diode oscillators can be tuned electronically also. Tunnel diode oscillators which are meant to be operated at microwave frequencies, generally used some form of transmission lines as tunnel circuit. These oscillators are useful in application that requires a few millwatts of power, example- local oscillators for microwave super hectrodyne receiver.

















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CHAPTER 6 APPLICATIONS TO TELECOMMUNICATIONS















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To further illustrate the Cellonics™ inherent Carrier -rate Decoding™, an FSK - like signal is taken as an example5. As shown in Fig 4b, the information symbols are encoded in this FSKlike signal that is transmitted through the channel. At the receiver, the Cellonics™ circuit produces different sets of pulses with respect to the different frequencies of the signal. The information symbol can be recovered by simply counting the pulses i.e. f1 produces 2 spikes, f2 produces 3spikes, f3 produces 4 spikes etc.















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require power hungry subsystems as mentioned earlier. With the Cellonics technology, a very simple receiver architecture can be realized without oscillators, phase lock loops etc. This is a paradigm shift in design.















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This is achieved using different number of spikes per cycle to represent different sets of information symbols (Fig 4g below).















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CHAPTER 7 PERFORMANCE OF CELLONICS RECEIVER 7.1. BER Performance in Narrowband

An important performance measure of any modulation scheme is its bit-error rate (BER) performance in a noisy channel. Fig 5a shows the numerical numerical simulation results of the Cellonics receiver in the AWGN channel. channel. Also shown in the figure is the theoretical curve of the optimal Binary Phase Shift Keying (BPSK) modulation scheme. From the figure, it is

















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CHAPTER 8 PROOF OF CONCEPT - DEMONSTRATION ON SYSTEMS















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simply counts the pulses to determine if it is a logic „1‟ or „0‟. The recovered data is then output to an audio player for real time playback. Note: This demo highlights good long distance performance.















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demonstration system shows a high throughput of data transfer and is 3 times faster as compared to a commercial Radio LAN product. Note: This demo highlights better than current wireless LAN (11 Mbps) performance. 8.2. Ultra Wideband Audio System

















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Fig 6d shows the block diagram of a second UWB demonstration system that transmits real-















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few discrete components that are mostly passive and hence consume very little or negligible















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orginal seminae cellonics seminar report

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