|
|
| Line 1: |
Line 1: |
| [[File:quarter wave impedance transformer.svg|thumb|350px|Using a transmission line as an impedance transformer.]]
| | They are typically a free website that are pre-designed for enabling businesses of every size in marking the presence on the internet and allows them in showcasing the product services and range through images, contents and various other elements. Affilo - Theme is the guaranteed mixing of wordpress theme that Mark Ling use for his internet marketing career. Change the site's theme and you have essentially changed the site's personality. Out of the various designs of photography identified these days, sports photography is preferred most, probably for the enjoyment and enjoyment associated with it. By using this method one can see whether the theme has the potential to become popular or not and is their any scope of improvement in the theme. <br><br>As you know today Word - Press has turn out to be a tremendously popular open source publishing and blogging display place. After all, Word - Press is free, many of the enhancements for Word - Press like themes and plugins are also free, and there is plenty of free information online about how to use Word - Press. It allows Word - Press users to easily use HTML5 the element enable native video playback within the browser. This is identical to doing a research as in depth above, nevertheless you can see various statistical details like the number of downloads and when the template was not long ago updated. Many times the camera is following Mia, taking in her point of view in almost every frame. <br><br>The entrepreneurs can easily captivate their readers by using these versatile themes. Note: at a first glance WP Mobile Pro themes do not appear to be glamorous or fancy. I've applied numerous Search engine optimization-ready Word - Press themes and I can say from knowledge that I consider the Genesis Search engine marketing panel one particular of the simplest to use. The first thing you need to do is to choose the right web hosting plan. If you've hosted your Word - Press website on a shared hosting server then it'll be easier for you to confirm the restricted access to your site files. <br><br>If you loved this post and you would like to obtain far more info concerning [http://www.nt-protect.host.sk/?wordpress_backup_plugin_99988 wordpress backup plugin] kindly go to the webpage. Digg Digg Social Sharing - This plugin that is accountable for the floating social icon located at the left aspect corner of just about every submit. Quttera - Quttera describes itself as a 'Saa - S [Software as a Service] web-malware monitoring and alerting solution for websites of any size and complexity. A higher percentage of women are marrying at older ages,many are delaying childbearing until their careers are established, the divorce rate is high and many couples remarry and desire their own children. The most important plugins you will need are All-in-One SEO Pack, some social bookmarking plugin, a Feedburner plugin and an RSS sign up button. If your blog employs the permalink function, This gives your SEO efforts a boost, and your visitors will know firsthand what's in the post when seeing the URL. <br><br>Internet is not only the source for information, it is also one of the source for passive income. I'm a large fan of using Word - Press to create pretty much any sort of web page. In simple words, this step can be interpreted as the planning phase of entire PSD to wordpress conversion process. In addition, Word - Press design integration is also possible. Customers within a few seconds after visiting a site form their opinion about the site. |
| A '''quarter-wave impedance transformer''', often written as '''λ/4 impedance transformer''', is a component used in electrical engineering consisting of a length of [[transmission line]] or [[waveguide]] exactly one-quarter of a [[wavelength]] (λ) long and terminated in some known [[electrical impedance|impedance]]. The device presents at its input the [[dual impedance|dual]] of the impedance with which it is terminated.
| |
| | |
| It is a similar concept to a [[stub (electronics)|stub]]; but whereas a stub is terminated in a short (or open) circuit and the length designed to produce the required impedance, the λ/4 transformer is the other way around; it is a pre-determined length and the termination is designed to produce the required impedance.
| |
| | |
| The relationship between the characteristic, ''Z''<sub>0</sub>, input, ''Z''<sub>in</sub> and load, ''Z''<sub>L</sub>, impedances is: <math>\frac{Z_\mathrm{in}}{Z_0}=\frac{Z_0}{Z_L}</math>
| |
| | |
| ==Applications==
| |
| [[File:LC to J-inverter filter.svg|thumb|350px|The [[lumped element model|lumped element]] [[low-pass filter]] (top) can be converted to a design that eliminates the inductors and contains capacitors only by the use of ''J''-inverters, resulting in a mixed lumped element and [[distributed element model|distributed element]] design.]]
| |
| | |
| At [[radio frequency|radio frequencies]] of upper [[VHF]] or higher up to [[microwave]] frequencies one quarter wavelength is conveniently short enough to incorporate the component within many products, but not so small that it cannot be manufactured using normal engineering tolerances, and it is at these frequencies where the device is most often encountered. It is especially useful for making an [[inductor]] out of a [[capacitor]], since designers have a preference for the latter.<ref name=Matthaei>Matthaei et al, pp.144-149.</ref>
| |
| | |
| Another application is when [[direct current|DC]] power needs to be fed into a transmission line, which may be necessary to power an active device connected to the line, such as a switching [[transistor]] or a [[varactor diode]] for instance. An ideal DC voltage source has zero impedance, that is, it presents a [[short circuit]] and it is not useful to connect a short circuit directly across the line. Feeding in the DC via a λ/4 transformer will transform the short circuit into an open circuit which has no effect on the signals on the line.<ref name=Bhat>Bhat & Koul, p.686.</ref> Likewise, an open circuit can be transformed into a short circuit.<ref>Bhat & Koul, pp.601-602.</ref>
| |
| | |
| The device can be used as a component in a [[distributed element filter|filter]] and in this application it is sometimes known as an inverter because it produces the mathematical inverse of an impedance. Impedance inverters are not to be confused with the more common meaning of [[power inverter]] for a device that has the inverse function of a [[rectifier]]. Inverter is a general term for the class of circuits that have the function of inverting an impedance. There are many such circuits and the term does not necessarily imply a λ/4 transformer. The most common use for inverters is to convert a 2-element-kind<ref>A 2-element-kind network is one consisting of only two kinds of elements, that is, ''[[LC circuit|LC]]'', ''[[RC circuit|RC]]'' or ''[[RL circuit|RL]]'' circuits.</ref> ''LC'' filter design such as a ladder network into a one-element-kind filter. Equally, for [[bandpass]] filters, a two-resonator-kind (resonators and anti-resonators) filter can be converted to a one-resonator-kind. Inverters are classified as ''K''-inverters or ''J''-inverters<ref>The ''K'' and ''J'' notation originates in archaic symbols for impedance and admittance respectively. The ''K'' is the same ''K'' that makes an appearance in the well known [[constant-k filter]] and the ''K'' parameter is defined for inverters of [[lumped element model|lumped element]] design in exactly the same way as it is defined for the constant-k filter. For a λ/4 transformer the difference is moot, the same device will serve as a ''K''-inverter with an inverter parameter of ''K''=''Z''<sub>0</sub> or equally as a ''J''-inverter with an admittance inverter parameter of ''J''=''Y''<sub>0</sub>, the characteristic admittance (=1/''Z''<sub>0</sub>).</ref> depending on whether they are inverting a series impedance or a shunt [[admittance]].<ref name=Matthaei/> Filters incorporating λ/4 inverters are only suitable for narrow band applications. This is because the impedance transformer line only has the correct electrical length of λ/4 at one specific frequency. The further the signal is from this frequency the less accurately the impedance transformer will be reproducing the impedance inverter function and the less accurately it will be representing the element values of the original lumped element filter design.<ref>Matthaei et al, pp.434-435.</ref>
| |
| | |
| ==Theory of operation==
| |
| [[File:SmithChartLineLength.svg|thumb|right|400px|Quarter-wave transformers are illustrated in an [[Smith chart|impedance Smith chart]]. Looking towards a load through a length {{math|''l''}} of lossless transmission line, the normalized impedance changes as {{math|''l''}} increases, following the blue circle. At {{math|''l''{{=}}λ/4}}, the normalized impedance is reflected about the center of the chart.]]
| |
| [[File:Transmission line animation open short.gif|thumb|right|300px|Standing waves on a transmission line with an open-circuit load (top), and a short-circuit load (bottom). Colors represent voltages, and black dots represent electrons. A quarter-wavelength away from the open-circuit, the current and voltage oscillations are exactly the same as at a short-circuit, and vice-versa. This reflects the fact that open circuit ({{math|''Z''{{=}}∞}}) is dual to short circuit ({{math|''Z''{{=}}0}}).]]
| |
| A transmission line that is terminated in some impedance, ''Z''<sub>L</sub>, that is different from the [[characteristic impedance]], ''Z''<sub>0</sub>, will result in a wave being reflected from the termination back to the source. At the input to the line the reflected voltage adds to the incident voltage and the reflected current subtracts (because the wave is travelling in the opposite direction) from the incident current. The result is that the input impedance of the line (ratio of voltage to current) differs from the characteristic impedance and for a line of length ''l'' is given by;<ref name=Connor>Connor, pp.13-16.</ref>
| |
| | |
| :<math>Z_\mathrm{in}=Z_0 \frac{Z_L + Z_0\tanh(\gamma l)}{Z_0 + Z_L\tanh(\gamma l)}</math>
| |
| :where ''γ'' is the line [[propagation constant]].
| |
| | |
| A very short transmission line, such as those being considered here, in many situations will have no appreciable [[insertion loss|loss]] along the length of the line and the propagation constant can be considered to be purely imaginary [[phase constant]], ''iβ'' and the impedance expression reduces to,<ref name=Connor/>
| |
| | |
| :<math>Z_\mathrm{in}=Z_0 \frac{Z_L + iZ_0\tan(\beta l)}{Z_0 + iZ_L\tan(\beta l)}</math>
| |
| | |
| Since ''β'' is the same as the angular [[wavenumber]],
| |
| | |
| :<math>\beta=\frac{2\pi}{\lambda}\ ,</math>
| |
| | |
| for a quarter-wavelength line, | |
| | |
| :<math>l=\frac{\lambda}{4}\ ,</math> <math>\beta l = {\pi \over 2}\ ,</math>
| |
| | |
| and the impedance becomes,
| |
| | |
| :<math>Z_\mathrm{in}=Z_0 \frac{Z_L + iZ_0\tan({\pi \over 2})}{Z_0 + iZ_L\tan({\pi \over 2})}=Z_0 \frac{iZ_0\tan({\pi \over 2})}{iZ_L\tan({\pi \over 2})}=\frac{{Z_0}^2}{Z_L}</math>
| |
| | |
| which is the same as the condition for dual impedances;
| |
| | |
| :<math>\frac{Z_\mathrm{in}}{Z_0}=\frac{Z_0}{Z_L}</math>
| |
| | |
| ==Notes==
| |
| {{reflist|2}}
| |
| | |
| ==References==
| |
| *Bharathi Bhat, Shiban K. Koul, ''Stripline-like transmission lines for microwave integrated circuits'', New Age International, 1989 ISBN 81-224-0052-3.
| |
| *F.R. Connor, ''Wave Transmission'', Edward Arnold Ltd., 1972 ISBN 0-7131-3278-7
| |
| *George L. Matthaei, Leo Young and E. M. T. Jones, ''Microwave Filters, Impedance-Matching Networks, and Coupling Structures'' McGraw-Hill 1964.
| |
| | |
| [[Category:Linear filters]]
| |
| [[Category:Filter theory]]
| |
| [[Category:Analog circuits]]
| |
| [[Category:Electronic design]]
| |
| [[Category:Distributed element circuits]]
| |
They are typically a free website that are pre-designed for enabling businesses of every size in marking the presence on the internet and allows them in showcasing the product services and range through images, contents and various other elements. Affilo - Theme is the guaranteed mixing of wordpress theme that Mark Ling use for his internet marketing career. Change the site's theme and you have essentially changed the site's personality. Out of the various designs of photography identified these days, sports photography is preferred most, probably for the enjoyment and enjoyment associated with it. By using this method one can see whether the theme has the potential to become popular or not and is their any scope of improvement in the theme.
As you know today Word - Press has turn out to be a tremendously popular open source publishing and blogging display place. After all, Word - Press is free, many of the enhancements for Word - Press like themes and plugins are also free, and there is plenty of free information online about how to use Word - Press. It allows Word - Press users to easily use HTML5 the element enable native video playback within the browser. This is identical to doing a research as in depth above, nevertheless you can see various statistical details like the number of downloads and when the template was not long ago updated. Many times the camera is following Mia, taking in her point of view in almost every frame.
The entrepreneurs can easily captivate their readers by using these versatile themes. Note: at a first glance WP Mobile Pro themes do not appear to be glamorous or fancy. I've applied numerous Search engine optimization-ready Word - Press themes and I can say from knowledge that I consider the Genesis Search engine marketing panel one particular of the simplest to use. The first thing you need to do is to choose the right web hosting plan. If you've hosted your Word - Press website on a shared hosting server then it'll be easier for you to confirm the restricted access to your site files.
If you loved this post and you would like to obtain far more info concerning wordpress backup plugin kindly go to the webpage. Digg Digg Social Sharing - This plugin that is accountable for the floating social icon located at the left aspect corner of just about every submit. Quttera - Quttera describes itself as a 'Saa - S [Software as a Service] web-malware monitoring and alerting solution for websites of any size and complexity. A higher percentage of women are marrying at older ages,many are delaying childbearing until their careers are established, the divorce rate is high and many couples remarry and desire their own children. The most important plugins you will need are All-in-One SEO Pack, some social bookmarking plugin, a Feedburner plugin and an RSS sign up button. If your blog employs the permalink function, This gives your SEO efforts a boost, and your visitors will know firsthand what's in the post when seeing the URL.
Internet is not only the source for information, it is also one of the source for passive income. I'm a large fan of using Word - Press to create pretty much any sort of web page. In simple words, this step can be interpreted as the planning phase of entire PSD to wordpress conversion process. In addition, Word - Press design integration is also possible. Customers within a few seconds after visiting a site form their opinion about the site.