This program was created to illustrate what happens when different passive components are connected and fed at high frequencies. With the help of the computer's capabilities, there is an opportunity to analyze analog passive filters with a frequency analyzer, without access to expensive electronic equipment.
Filters that can be simulated are RC filter, LC filter, LP filter, HP filter, BP filter, BS filter, and other circuits.
The basic connection is an asymmetrical four-pole and a reference potential (ground) for both the input and the output of the filter.
You can choose between three different types of connections. These are A, B, or C. A is the most common, a straight filter. For a B filter, there is the option of inserting a bypass, i.e. a second filter or connections in parallel above the A filter. For the C connection, it is also possible to create a bypass that terminates at any location in the A filter.
The order number is at a maximum of 20 for an A filter, 40 for a B filter, and 60 for a C filter - excluding generator and load component.
Different filter designs are tested in a simulator that shows the filter's transfer function, phase, and impedance characteristics in relation to the selected frequency range. The amplification and/or attenuation are also presented.
The sentence by a transfer function is the ability to block or let through the amplitude of an incoming sinusoidal alternating voltage. You thus obtain an amplitude response which is usually the same value or less depending on its frequency.
The cutoff frequency markings can be presented.
Tried filters can be saved in a file with the extension .pfs.
Perhaps you have wondered what happened when you tested your own HF builds and it turns out not to work as it should. The cause of the problem is often that the components you use, i.e. capacitors, coils, and resistors no longer perform as intended. In fact, at high frequencies, these three components begin to take on the characteristics of each other. In HF couplings, it is no longer possible to consider components as pure capacitors, coils, or resistors.
How these interact with each other can be interesting to know but that can also be left to this application. To see how a component can be diagrammed based on the above, you can select a component in the main menu and then study the equivalent diagram. The skin effect and leg length are other factors that are calculated. All this means that almost all pitfalls are eliminated and almost a completely correct model is created. Note that the input impedance of the filter is measured after the generator impedance. The input impedance also includes the load.
In the application, there is also a flexible calculation section for calculating various air-wound coil constructions where even straight wires can be calculated and used as inductances or antennas. Otherwise, you can use one of those that already come with the application. There are some components ready to take off. Coils or chokes that have an inductance-increasing core (with a bobbin) deviate from the equivalent scheme, but this mainly applies when calculations are made above the resonant frequency of the coil/choke. When you want to replicate a coil/choke based on the make and which you want to use, then it is important to find an approximate value for the diameter of the coil wire. A deviating wire diameter increases or decreases the internal resistance of the coil and then the Q value is also affected. This leads to an incorrect model of the inductance which is created!
In order for your build to work as intended or as the application shows, you should not neglect the choice of component type. Especially at high frequencies, the characteristics of components should be taken into account. If you read the information for the selected component, it is possible to study the performance and area of use for different types. You can then select a type from the drop-down menu. Resistors that can be recommended are thick film/SMD, metal film, or carbon composition resistors. Capacitors that can be recommended are SMD, ceramic class 1, or mica capacitors.
You thus start by choosing the filter type and order number. It is possible to step up or down the order number at a later stage via a drop-down menu (due to lack of space or excess), without destroying the connection. If, on the other hand, you choose to step down, the components furthest away are eliminated if they do not consist of open circuits or short circuits.
You can choose to work with ideal or real components. Ideal components are perfect, i.e. - missing stray components. If it concerns audio systems, it is fine to only use ideal ones, for higher frequencies you have to choose real components and keep the leg lengths short.
To see what data each component has, simply move the mouse pointer over the component or an element. If you left- or right-click on the element, you can choose to edit or switch to another component. It is also possible to retrieve a new component from a file, move, copy, or create a resonant circuit. You can also choose an open circuit or a short circuit. Open circuits or short circuits count as real components but are in fact an ideal resistance.
If space matters, then you can open the element view window by clicking the EV button. The element/component is then visible in this window instead of under the filter coupling.
To be able to read a resonant circuit, you have to move the mouse pointer out of the filter coupling and back again to switch components. If the value above the component shows zero, you should change the multiple units in the drop-down menu. There you can also choose whether you want to calculate the loss factor (%) or the resistance (mΩ) regarding the capacitor's ohmic losses.
The nominal value over an element can be changed up or down by rotating the mouse wheel, which makes it possible to easily adjust different elements during the simulation - at the same time the curves move. The input voltage can also be changed. The nominal input voltage is 1V and the nominal input and output resistance is 50Ω for a new filter, but this can be chosen completely to your liking. If desired, the generator component can be replaced with a short circuit or any component. The load can be, for example, an open circuit for maximum resistance.
A filter element retrieved from a file can be modified arbitrarily like any other component. If you consider that the component's values start to deviate from the file it came from, then you can remove the file name. Choose edit - in the first field (ohm, capacitance, or inductance) enter "0" which then removes the file name without changing the original value.
It is possible to shift between different filter types (A, B, and C) through the button "TF" (TransFer). Before starting a transfer, you should first have saved your filter. It is possible to make all conceivable transports between filter types, which means that when you shift between a larger type to a smaller one, there is always a loss of data. A completed transfer cannot be undone, so you have to be careful.
The simulation begins by selecting a voltage, impedance, and frequency via the Graph control. Namely, the voltage and the impedance curve can drift upwards or downwards so that it becomes impossible to take a reading. To read a quantity, you can place the mouse cross on the intended position and read its value. Keep in mind that the mouse cross does not take into account several quantities at the same frequency, so the cross must be placed individually on each curve that is presented. The highest accuracy is achieved by selecting the largest possible curve drawing window.
The cutoff frequency markings can, if the circumstances permit, end up aside. It happens if the curve shape of the transfer function deviates from the normal. To ensure that the placements end up correctly, you should zoom in on the area you want to review.
Type B filters included in both B and C filters have proven difficult to calculate. If one parallel network is an open circuit while having a low output impedance, then the impedance will affect the next network. The load will then increase. Pfsim can calculate this but with some limitations. The factor determines when the backward impedance should be included. The backward impedance is referred to here as "super impedance" and is the impedance between the filter and ground. A high factor prevents the net containing the filter itself from counting on its super impedance. If it were to happen, the curve shape of the transfer function would be affected, not infrequently with spectacular flank jumps up and down. One can look at the color of the curve when the super impedance is activated. It alternates between yellow and cyan. A factor value of around 3000 prevents normal filter couplings from ending up in the super impedance mode, but this also depends on how the filter is configured. You can control this yourself. 3000 means that the input impedance of one network must be less than 3000 times its super impedance.
The impedance for B and C filters is calculated in different ways depending on whether there are real or ideal components in the coupling. If there are real components the total impedance is calculated in the traditional way, which means that the total impedance tends to be too low. If there are no real components (only ideal), the total impedance is calculated more accurately. However, the accurate method conflicts with how a real filter behaves, especially where resonances occur. A wavy equal sign appears in the impedance representation when the calculation is done accurately and a question mark when it is done traditionally. If you want to be sure that the calculations are always done traditionally, just insert a real component somewhere in the coupling - only applies to B and C! Open or shorted element has no relevance regarding this rule.
The impedance for B and C filters is not exact, but if you stick to "normal filter circuits", you should be pretty accurate, based on what happens in reality. However, if you choose to build unconventional circuits in B and C, then this application may not be the right choice.
Calculations of impedances and voltages are done with the j-omega method and are constantly updated as long as the curve drawing window is open. Thanks to the j-omega method, the phase ratio of the output voltage can be easily calculated, which facilitates the dimensioning of so-called phase-shifting filters.
The contents of folder R\
R_CC405.ele = Carbon composition
R_CF405.ele = Carbon film
R_MF405.ele = Metal film
R_MO405.ele = Metal oxide
R_SMD22.ele = Surface mounted
R_ThickF405.ele = Thick film
R_ThinF405.ele = Thin film
405 means that the leg length is 4mm and the wire thickness is 0.5mm.
22 = both length and diameter are 2mm.
All resistors have a value of 1 ohm.
The contents of folder C\
C_CC1405.ele = Ceramic class 1
C_CC2405.ele = Ceramic class 2 & 3
C_M405.ele = Mica capacitor
C_PC405.ele = Polycarbonate capacitor
C_PE405.ele = Polyester capacitor
C_PP405.ele = Polypropylene capacitor
C_SMD122.ele = Surface mounted class 1
C_SMD222.ele = Surface mounted class 2 & 3
405 means that the leg length is 4mm and the wire thickness is 0.5mm.
22 = both length and diameter are 2mm.
All capacitors have a value of 1 pF.
The contents of folder L\HF-air wound\ (wires & air wound coils)
Coil40nH.ele = 40nH
Coil50nH.ele = 50nH
Coil60nH.ele = 60nH
Coil70nH.ele = 70nH
Coil80nH.ele = 80nH
Coil90nH.ele = 90nH
Coil100nH.ele = 100nH
Coil110nH.ele = 110nH
Coil120nH.ele = 120nH
Coil130nH.ele = 130nH
Coil140nH.ele = 140nH
Coil150nH.ele = 150nH
Coil160nH.ele = 160nH
Coil170nH.ele = 170nH
Coil180nH.ele = 180nH
Coil190nH.ele = 190nH
Coil200nH.ele = 200nH
Coil220nH.ele = 220nH
Coil240nH.ele = 240nH
Coil260nH.ele = 260nH
Coil280nH.ele = 280nH
Coil300nH.ele = 300nH
Coil320nH.ele = 320nH
Coil340nH.ele = 340nH
Coil360nH.ele = 360nH
Coil380nH.ele = 380nH
Coil400nH.ele = 400nH
Coil420nH.ele = 420nH
Coil440nH.ele = 440nH
Coil460nH.ele = 460nH
Coil480nH.ele = 480nH
Coil500nH.ele = 500nH
Coil520nH.ele = 520nH
Coil540nH.ele = 540nH
Coil560nH.ele = 560nH
Coil580nH.ele = 580nH
Coil600nH.ele = 600nH
Wire5nH.ele = 5nH
Wire10nH.ele = 10nH
Wire15nH.ele = 15nH
Wire20nH.ele = 20nH
Wire25nH.ele = 25nH
Wire30nH.ele = 30nH
Wire35nH.ele = 35nH
Wire40nH.ele = 40nH
Wire45nH.ele = 45nH
Wire50nH.ele = 50nH
Manufacturing data: Air_Coils.txt