1. Introduction 2. Getting Start
Contents
1. dec n fstart fstop Octave s native statements are helpful for example to process data or figures to perform parameter sweep simulation using loop or conditional branch and so on Octave s syntax supports the Sha Bang Thus you can even make your spdc netlist a standalone executable by adding the following line to the head of netlist and adding executable permission to the file usr bin env spdc Then you can run simulation by either of the following shell commands spdc your circuit netlist file your circuit netlist file 3 Modeling 3D Distributed Circuit In spdc 3D distributed circuit in a cuboid zone is discretized to repeated cubic circuit cells The following figure shows one of the cubic cells where n means circuit node b means circuit branch e means electric circuit m means magnetic circuit ne bey ne 4 r bex bmz bex A 4 ne bey ne bez bmx bez DMY j nm a bmy pez bmx 3 bez an y ne bey ne gt ef bex bmz bex Va A bey ne ne Ce In this model electric circuit and magnetic circuit are interlaced the cell size branch length is 2 grids so each cell contains 8 grids which are listed below Grid type Symbol Position in the cell Electric circuit node ne 0 0 0 Electric circuit branch along x direction bex 1 0 0 Electric circuit branch along y direction bey 0 1 0 Electric circuit branch alon2. Electro branch motiveforce fe 1 0 0 E 2 dx 0 1 0 Electro branch voltagedrop de 0 0 1 E 2 dx Electro branch current ie J 2 dx Magnet node voltage vm 111 Pa Magnet branch motiveforce fm 0 1 1 H_ 2 dx 1 0 1 Magnet branch voltagedrop dm 1 1 0 H 2 dx Magnet branch current im J_ 2 dx The node voltage is the scalar potential of branch voltagedrop which satisfies KVL while branch motiveforce can also be considered as the vector potential of branch current which satisfies KCL spdc s simulate command only gives those potentials which are less redundant All the other data will be got by post simulation data process method Besides voltagedrop plus motiveforce just equals the total field E E E H H H _ which is concerned by electromagnet field simulators while spdc mainly concerns voltage and current as Spice does 4 spdc Commands Once you start spdc and get into the interpreter begin with the following command to list all spdc commands and then see the separate help text for each command for detail sp help 4 1 Circuit Description These commands correspond to Spice s instantiation statements sp circ sp circ sp circ sp circ sp circ sc SCX SCY SCZ bc 0 1 gc rc cc lc X Y Z VALUE vpe vpm ipe ipm X Y Z PORT vd id PORT DIRX DIRY DIRZ sp_stim vs is PORT ac MAG PHASE dc VALUE sp_stim vs is PORT ac MAG PHASE pwl T1 V1 T2 V2 Sp stim vs is PORT
3. ac MAG PHASE pulse V1 V2 TD TR TF Pw PER sp stim vs is PORT ac PHASE MAG PHASE sin VO VA FREQ TD THETA spdc also provides the following commands to help you draw complex geometric patterns conveniently sp draw sp draw sp draw sp draw sp draw sp draw sp draw sp draw sp draw sp draw sp draw ls rm mv cp PARAM VALUE im X Y Z FILE eX ELE ao ie Marner new X YZ mov ext drw mov ext drw mov ext drw mov ext drw mov ext drw shf rot pnt axs pln N DIST TX TY TZ N PHASE PX PY PZ TX TY TZ N SCALE PX PY PZ N SCALE PX PY PZ TX TY TZ N SCALE PX PY PZ NX NY NZ Notice each type of data s cell position to set value to a datum out of its position s will take no effect One method to avoid this is to extend your pencil size to at least the cell size 2x2 x2 4 2 Analyses These commands are as the same as the corresponding Spice commands op ac tran Sp_op sp_ac lin oct dec N FSTART FSTOP sp tran TSTEP TSTOP TSTART 4 3 Output Control Not only spdc can plot curves of waveform spectrum as Spice s plot command does but also it can plot 3D distributions of data like field simulators sp plot tran vs is PORT UNIT sp plot tran ve vm X Y Z UNIT sp plot tran fex fey fez fmx fmy fmz X Y Z UNIT sp plot tran dex dey dez dmx dmy dmz X Y Z UNIT sp plot tran iex iey iez imx
4. imy imz X Y Z UNIT sp plot ac vs is r i m p PORT UNIT sp plot ac ve vm r ilm p X Y Z UNIT sp plot ac fex fey fez fmx fmy fmz r ilm p X Y Z UNIT sp plot ac dex dey dez dmx dmy dmz r ilm p X Y Z UNIT sp plot ac iex iey iez imx imy imz r ilm p X Y Z UNIT sp plot linlin linlog loglin loglog sp plot3 dc tran ac gc rc cc lc vpe vpm ipe ipm n UNIT sp plot3 dc fe fm de dm ie im n UNIT sp plot3 tran fe fm de dm ie im n T UNIT sp _plot3 ac fe fm de dm ie im n r i F UNIT spdc s set circuit and simulate commands only give basic packed data since this can save memory and all the other data can be calculated from them Therefore you should calculate unpack the data before plotting them The following commands manipulate the unpacked data sp post gc rc cc lc vpe vpm ipe ipm sp post ve vm fe fm de dm ie im sp_reset gc rc cc lc vpe vpm ipe ipm sp_reset ve vm fe fm de dm ie im Notice each type of data s cell position to evaluate a datum out of its position s will get zero values 4 4 Miscellaneous The following command is as the same as Spice s include command sp include FILE You may want to save your circuit or simulation results so as not to spend cputime on it again later The following commands manipulate the basic packed data sp save FILE c r a sp_ load FILE c r a sp_clear c rla 4 5 Ngspice Interactive T
5. g z direction bez 0 0 1 Magnetic circuit node nm 1 1 1 Magnetic circuit branch along x direction bmx 01 1 Magnetic circuit branch along y direction bmy 1 0 1 Magnetic circuit branch along z direction bmz 1 1 0 Thus in spdc each node or branch can be identified by its unique 3D coordinate compared with Spice in which node or branch is identified by its name This is a main difference between spdc netlist and Spice netlist 3 1 Circuit Parameters In spdc the circuit s cuboid size sc should be set first of all which specifies the whole simulate zone Then every object s 3D coordinate x y z should be limited in the range of the cuboid size i e 1Sx lt scx 1 lt ysscy 1Szsscz The boundary condition bc also should be given spdc provides two types of boundary condition including short electro circuit open magnet circuit and open electro circuit short magnet circuit Other types of boundary condition can be realized by set circuit parameters near the boundary to proper values Circuit parameters include the following Parameter Symbol Position Value Electro branch conductance gc 1 0 0 o 2 dx Electro branch capacitance cc n a T 2 dx Magnet branch conductance rc 0 1 1 o 2 dx Magnet branch capacitance lc i i a uou 2 dx Magnet capacitance can be set to zeros if you do not want to take account of inductance in simulation Magnet conductance can be set to zeros if magne
6. he above commands are similar to Spice s command set Furthermore spdc can also export distributed circuit to Ngspice netlist edit it for stimuli and analysis type call Ngspice simulator and then import the corresponding Ngspice simulation result All of these can be done without exiting spdc but this needs Ngspice installed on your system sp _nglist FILE sp _ngrun FILE sp_ngload FILE You may want to view or edit any text file without exiting spdc then the following command does sp edit FILE
7. ke some Spice programs such as Ngspice What s more you can also pass any Octave s options to spdc at start spdc octave options your circuit netlist file 2 2 Writing Netlist The netlist which spdc reads is close to Spice netlist though it is difficult to be totally as the same as Spice since spdc has to describe 3D objects while Spice mainly describes lumped circuit As seen by Octave an spdc netlist is actually an Octave script In the netlist you can use spdc provided Spice style commands as well as any Octave s statements you like The spdc commands are implemented as a set of Octave functions but their usages appear to be Spice style All of them begin with sp _ in order to be different from Octave s native function or command names to prevent from overloading You will see that usually replacing the prefix dot of a Spice command with sp will get the corresponding spdc command Each spdc command accepts either string or number argument where it excepts a number This makes it possible to write your netlist using Octave s command format which just accepts string arguments like Spice netlist style For example the following statements will perform the same ac simulation sp_ac dec 10 le 3 1le 9 sp_ac dec 10 le 3 1le 9 sp_ac dec 10 1e 3 1e 9 sp_ac dec n 10 fstart le 3 fstop le 9 sp_ac dec n 10 fstart 1le 3 fstop 1le 9 n 10 fstart le 3 fstop le 9 sp ac
8. spdc user manual 1 Introduction 1 1 What is spdc spdc stands for simulation program for distributed circuit spdc is a simulator for 3D linear time invariant isotropic distributed circuit Given 3D distributions of circuit parameters such as electro magnet conductance and capacitance and stimuli such as voltage and current source spdc will figure out the 3D distributions as well as the waveform spectrum of responses such as voltage current and so on 1 2 With Spice Classical circuit simulators that can work with distributed circuit such as the well known Spice Simulation Program for Integrated Circuit Emphasis mainly focus on 1D uniform distributed transmission line However spdc is a full 3D arbitrary distributed circuit simulator In fact it is like an electromagnet field simulator in some degree 1 3 With Field Simulator Electromagnet field simulators mainly work on the field view figuring out electric field and magnetic field Although spdc can also calculate electromagnet field it is designed to provide a circuit view focusing on such as voltage and current which might be more familiar to circuit designers 2 Getting Start 2 1 Running spdc spdc is based on GNU Octave but is designed to be close to Spice so that it is easy for circuit designers who are familiar with Spice Open a terminal and type spdc followed by an optional netlist file to run simulation after that you will get into an interpreter li
9. tic medium s loss can be ignored and if there is no magnetic monopole in the world 3 2 Ports and Stimuli Stimuli include branch voltage source and branch current source as Spice does Instead of directly adding stimuli to the circuit branches the electro magnet circuits together are first labeled with several voltage ports and several current ports see below tables each port is then defined with a direction vector and finally add stimuli to each port As a result all the zones which belong to the same port will be added with the same stimulus along the same direction This makes it easy to set stimuli because the port number is usually much smaller than the branch number Parameter Symbol Position Value Electro branch voltage port index vpe 1 0 0 voltage port index 010 Electro branch current port index ipe 0 current port index Magnet branch voltage port index vpm voltage port index Magnet branch current port index ipm current port index Parameter Symbol Index Value Branch voltage port direction vector vd vpe vpm vdx vdy vdz Branch current port direction vector id ipe ipm idx idy idz Parameter Symbol Index Value Branch voltage port source vs vpe vpm E 2dx H 2 dx Branch current port source is ipe ipm J 2dxf J 2 dx es ms 3 3 Responses Responses include the following Parameter Symbol Position Value Electro node voltage ve 0 0 0 PE
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