Two-port network

Figure 2 illustrates a two-port network large-signal equivalent model appropriate for TTFT modeling. The gate-source is the input port and the drain-source is the output port. 

Circuits like these can be looked upon as a black box , with two terminals coming in (the input, or the excitation) and two leaving (the output, or the response). One of the rails may of course be common to both the input and output, as in the case of the ground rail. This forms a two-port network . Such an approach is useful, because power supplies too, can be thought of in much the same way — with two terminals coming in and two leaving, exposed to various disturbances/stimuli/excitations. 

The output of this network is taken to be the voltage across the capacitor, which we now call v0 here. Note that v0 is a function of time. We define the ratio of the output to the input of any such two-port network, i.e. v0/vi in this case, as the transfer function . Knowing how the RC network behaves, we also know the transfer function of this two-port network, which is... 

Note that in general, a transfer function need not be Volts/Volts (dimensionless). In fact, neither the input nor the output of a two-port network need necessarily be voltage, or even similar quantities. For example, a two-port network can be as simple as a current sense resistor. Its input is the current flowing into it, and its output is the sensed voltage across it. So, its transfer function has the units of voltage divided by current, that is, resistance. Later, when we analyze a power supply in more detail, we will see that its pulse width modulator ( PWM ) section for example, has an input that is called the control voltage , but its output is the dimensionless quantity — duty cycle (of the converter). So the transfer function in this case has the units of Volts-1. 

In Fig.5, the relation between Vi, V2, h and I2 (the input and output voltages and currents of a two port network in the frequency-domain) is represented by ... 

Where, the ABCD coefficients are generally complex functions of frequency, and fully characterize the electrical properties of a two port network. 

Fig. 7. Basic voltage and current definitions for Two-Port Network with distributed branches...

Noise figure Ratio of actual noise output of an actual two-port network to fictitious ideal noise output of an ideal network that does not produce noise within the circuit but has transferable noise from the input. The ratio of the input S/N ratio to the output S/N ratio. 

Sensitivity Amount of input signal power to a two-port network that produces a designed signal-to-noise ratio at the output. 

Figure 1. Description of the system of a Li-ion cell or battery, which is a two-port network. The upper graph shows the system in time domain and the lower graph shows the system in frequency domain. The input signal is the current excitation and whereasthe output signal is the voltage response.

At the other end of the spectrum, there are 3335 external hosts that sent exactly one TCP flow into the monitored network during the analyzed time interval. Of these, only two port and flag combinations appear more than 100 times. SYN probes for port 88663 are seen 449 times. SYN probes for port 25 (SMTP email) are seen 271 times. The vast majority of the remainder are SYNs to a variety of ports, mostly with high port numbers. There are a number of ACK/RST packets which are probably associated with responses to spoofed DDoS attacks. 

Two-port devices include SAW, FPW, and APM delay lines and the two-port-resonator variations of these devices. For all the delay lines, the transmitted signal S]2 (between ports) is most important Just as in one-port measurements, a network analyzer is the instrument of choice to measure frequency response the setup is depicted in Figure 6.9(a) (page 362). Frequency response can also be measured using the synthesized oscillatorA VM combination shown in Figure 6.9(b). As for the one-port measurements, this setup is most convenient when computer controlled. 

Figure 6.9 (a) Use of a network analyzer to measure two-port-device frequency response. (b) Setup for measuring two-port frequency response using the synthesized os-cillatorA VM combination. 

The aim of network analysis is the investigation of the amplitude and phase response of a two- or four-port network. Impedance analysis determines the complex impedance or admittance of a device. This method is appropriate for quartz resonators in order to obtain more complete information than is conceivable by merely considering the shift of the resonance frequency. The method especially allows the determination of the equivalent circuit elements (BVD) presented in Fig. 8. Actually many commercial instriunents directly provide this information. Determination of the physical parameters, or their effective values, for accurate modeling of the sensor behavior based on Eq. 5 requires mathematical procedures which fit the calculated curves (e.g., with Eq. 2) to the experimentally measured values. It is recommended to include an external capacitance parallel to Co to accoimt for uncompensated para-... 

Three-electrode systems correspond to a two port, three-terminal network equivalent (see Section 7.1). Because there are two ports, it is the transfer parameters that are measured even if one CC and one PU electrode are common. Figure 7.23 shows the principle (Grimnes, 1983a). The current flows between the M and C electrodes and the R electrode is a PU electrode without current flow. 

If the effect of the zones proximal to the current carrying electrodes and the polarization impedance of the electrodes themselves are to be reduced, the four-electrode system is preferred. Such four-electrode systems correspond to a two-port, four-terminal network equivalent (see Section 8.1). Because there are two ports, these systems actually measure transfer parameters between the ports. This means that if for instance impedance is measured to 0 O, this does not necessarily imply high-conductivity tissue, but rather no signal transfer from CC to PU electrodes. 

A one-port (dipolar) electrode system measures immittance. The two electrodes function both as CC and PU electrodes. A two-port four-electrode system measures transmittance (transfer immittance) for example, with current injected in one port and voltage recorded at the other port (the black box, Section 7.1). The electrode pairs of current injection and voltage recording may be interchanged if the reciprocity theorem is valid, the transmittance is the same. For the reciprocity theorem to be valid, there are no constraints on geometry, only on, for example, system linearity as outlined in Section 8.1.3. The reciprocity theorem is not based on geometry but on network theory, and is therefore treated in Section 8.1. 

The one-port two-electrode network measures the driving point immittance of the tissue without any transmission component. The two-port, four-electrode network measures the transfer immittance from one port to another. It can be completely defined with four ratios (constants) characterizing the network, and four variables. Here we will introduce two equation sets ... 

The two-component model with one resistor and one capacitor is a one-port network and is the simplest and most important model because every measurement on a specific frequency is reduced to such a circuit. The results are given as complex immittance values with two figures corresponding to the two components one resistor and one capacitor. Inductive properties and corresponding resonance phenomena are possibilities that are found, for example, in membranes, but here we limit the treatment to capacitive systems. 

In this chapter, the modeling procedures of power line channel have been presented. The deterministic method uses basic network parameters to derive a transfer function of the channel. The investigated deterministic models were determined from an indoor PLC channel. They are specifically topology dependent. For separate network channels, only the cable parameters, the load impedances and the topology of the network are absolutely needed. The LV network is considered as an M nodes and N branches, which is subdivided into several cascaded two-port of small networks. The transfer function of the channel is later obtained by combining easily the T-matrices of the cascades sub networks. The position of notches in frequency response depends on the length of the branched lines. The increase in branched line length tends to limit the available bandwidth in LV channel, but the... 

Two-port filter networks. The exclusion of some passive filters with multiple outputs is not as significant here as it would be in a discussion of active filters. 

There are scores of microwave devices that need to be measured. The most common measurements tirat are done are the frequency measurements, but we are also interested in phase measurements depending on the device under test (DUT). We can use various equipments like spectrum analyzer, vector network analyzer, etc. [33]. Most of the devices that we measure will be two-port devices that is, the input is applied at one port and the output is taken at the other port. So we will basically be measuring devices, a group of devices that form a part of tiie system, and microwave circuits. 

Our proof is immediately extended to include networks with arbitrary multi-port elements. At no point of the proof have we made use of the assumption that two different ports really belong to two different elements. We just have to beaip in mind that a direct connection between two ports is impossible since we have assumed associated reference directions for all ports. This means that every port of a 1- or multi-port element is necessarily connected either to a 0- or to a 1-junction. 

WAP. The WAP provides the wireless data communication service. It usually consists of a housing (which is constructed from plastic or metal depending on the environment it will be used in) containing a circuit board, flash memory that holds software, one of two external ports to connect to existing wired networks, a wireless radio transmitter/receiver, and one or more antenna connections. Typically, the WAP requires a one-time user configuration to allow the device to interact with the local area network (LAN). This configuration is usually done via a Web-driven software application which is accessed via a computer. 

The observations of the Black Sea level started in the middle of the 19th century. The longest observation series are available in Romania for the ports of Constanta and Sulin (since 1858), in the Ukraine (Ochakov, since 1874 Odessa and Sevastopol, since 1875), and Georgia (Poti, since 1874 and Batumi, since 1882). At present, the observation network of the Black Sea level includes 30 stations (of them, 13 in the Ukraine, five in the Russian Federation, four in Bulgaria, three in Romania, three in Turkey, and two in Georgia). During the past decade, the sea level is also studied with the use of satellites. 

There are two types of hubs active and passive. Passive hubs simply connect all ports together electrically and are usually not powered. Active hubs use electronics to amplify and clean up the signal before it is broadcast to the other ports. In the category of active hubs, there is also a class called intelligent hubs, which are hubs that can be remotely managed on the network. 

Let us present HDL s basic modeling elements. For a pictorial depiction of their character, see Fig. 16. The first three modeling elements are sufficient to represent the structure of any processing system. The following two elements are used to represent complex systems which consist of networks of instances of GenericUnit, Port, and Stream. 

There are two possibilities for getting the information wanted, both text and graphics, from a certain databases by choosing direct connection to an X.25 port with high transmission velocity and a protected line protocol of a packet switched network or by selecting the PAD-version (jacket Assembly Msassembly) with reduced and unprotected line protocols. 

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