Explore the World of Software: Engineering & Science

home *** CD-ROM | disk | FTP | other *** search

/ Explore the World of Soft…e: Engineering & Science / Explore_the_World_of_Software_Engineering_and_Science_HRS_Software_1998.iso / programs / electrnc / acnet.txt < prev next >

Wrap

Text File | 1997-09-18 | 38KB | 694 lines

*** ACNET - Electronic Circuit Simulator *** ------------------------------------ 1. INTRODUCTION ------------ ACNET is an electronic circuit simulation program which calculates the steady state performance of circuits containing any combination of resistors, capacitors, inductors, transformers, transistors (bipolar & FET), op-amps, mutual inductors and thermionic valves. The output shows the gain, phase shift, input and output impedances of the network at any given frequency and also provides gain plots over a wide frequency range. The circuit values are stored on disk. These may be modified at any time, extra components and nodes can be added or deleted, and input and output nodes redefined. Simple but comprehensive graph plotting facilities are also included, suitable for any text printer. Better quality is available for Epson (9 & 24 pin), IBM and HP DeskJet printers. Sixty predefined frequency scales extending up to 300MHz over a range of 1, 2 or 3 decades are provided together with the facility for user defined frequency scales over any range. Two versions of the simulation program are supplied - a software only version and an extended version which gives better accuracy and which can use a coprocessor if available. The program will run on any IBM compatible PC under DOS and requires 195KB of memory and preferably a hard disk (although it can be set up to run from two floppies). The software may be installed from a supplied batch file and is easy to use from either the keyboard or by means of a mouse, with menus and helplines provided. Default settings are automatically set - these may be changed by the user if required. The program can be used to calculate the performance of any linear circuit, such as audio, video, i.f. and r.f. amplifiers, active and passive filters, matching networks, etc. It can be used to evaluate the effectiveness of decoupling components and stability criteria of oscillators. Circuit examples are provided, including simple filters, a delay line, feedback amplifiers, TV IF amplifier, a gyrator, a mutually coupled tuned circuit, a valve amplifier, Baxandall audio tone control and a 9 band graphic equalizer. 2. FILES PROVIDED -------------- Your supplied disk contains the following files :- 1) README.TXT ............ This documentation 2) INSTALL.BAT ............ Installation program for Version 4.1 3) GPRINT.BAT ............ Print program for 24 pin and HP printers 4) ACNET.EXE ............ Circuit simulation program 5) ACNET_X.EXE ............ Extended circuit simulation program 6) ACNET.DEF ............ Defaults file used by simulation program 7) CIRCUITS.TXT ............ Circuit schematics 8) HPFILTER.DAT } 9) FBAMP2A.DAT } 10) DUBTUNE.DAT } 11) BANDPASS.DAT } 12) GYRATOR2.DAT } 13) NOTCH300.DAT } 14) VALVEAMP.DAT } 15) WHITEPNK.DAT } ......... Sample datafiles for use with ACNET 16) BAX4.DAT } 17) GRAPHEQ.DAT } 18) TVIFAMP3.DAT } 19) VIDEO1.DAT } 20) VIDEO2.DAT } 21) LINE.DAT } 22) RIAA.DAT } 23) CROSSOVR.DAT } 24) UNZIP.EXE ............ Decompression program 25) GRAPHS.ZIP ............ Sample graphfiles in compressed form. On installation these will expand to :- GRAPHS.TXT .......... Sample graphs using only printable chars GRAPHS.GRF .......... Sample graphs for Epson RX80 series printers GRAPHS.ELX .......... Sample graphs for Epson LX 9 pin printers GRAPHS.EFX .......... Sample graphs for Epson FX 9 pin printers GRAPHS.IBM .......... Sample graphs for IBM 24 pin printers GRAPHS.E24 .......... Sample graphs for Epson 24 pin printers GRAPHS.HPK .......... Sample graphs for Hewlett Packard printers 3. INSTALLATION ------------ The supplied files should be copied to your working disk - preferably a hard disk. The installation program INSTALL.BAT will do this for you, creating the appropriate directories - \NET_V4 for the main files, with subdirectories \DATFILES and \GRFFILES for the data and graphfiles. To install ACNET on drive C (for example), place a copy of the supplied disk in your input drive and set this as the current drive. Then type :- INSTALL C: Any other valid drive may be designated for the programs. Files created under previous versions are compatible with Version 4 after modification which is carried out automatically by this new version of ACNET. Thus existing datafiles you have already may be transferred to the new directory and used. Operation using two drives is covered later (see 6.7.1). 4. VERSIONS AVAILABLE ------------------ Two versions of the program are supplied - ACNET.EXE and an extended version ACNET_X.EXE. They are identical to the user and differ only in accuracy and speed. ACNET is a software only version adequate for most purposes. ACNET_X provides higher precision and range and consequently is slower. If you have a coprocessor fitted to your machine this will automatically be used by the extended version giving about the same speed as the normal version. So if a coprocessor is available, always use the extended version ACNET_X. Without a coprocessor use ACNET for speed, especially for graph plotting. However, if you are using a very wide range of circuit values you may find that some results, (most especially the input impedance), are somewhat inaccurate due to matrix rounding errors. Also it has been found that loading EMM386.EXE slows down the operation of the extended version if a coprocessor is not present. The programs supplied by the shareware vendors are limited to a maximum of 8 nodes when calculating the circuit response. You may obtain the full 50 node versions by registering with the author - see Section 11. 5. RUNNING ACNET ------------- To run, set the default directory to \NET_V4 and type ACNET or ACNET_X for the extended version. The screen (which is set for 80*25 characters) will show the program and system parameters and for ACNET_X confirmation of a co- processor if one is available. Also the mouse will be activated if present. Type <ESC> immediately on startup to disable the mouse if you wish. All references to ACNET apply to both versions unless otherwise stated. At the prompt press any key (mouse or keyboard) to continue. The last used datafile will be selected for you automatically and the Main Menu will be displayed. The default settings as supplied will select the file HPFILTER for you when you first start. This datafile contains values for a simple three element high pass passive filter (see CIRCUITS.TXT) and I suggest you use this initially to work through the menu options before defining your own circuits. The current revision number and a short message for the datafile will be displayed at the top of the screen. ACNET will run as a DOS based application from within Windows. However it should only be run full screen. Use <ALT><TAB> to minimize the program. 6. THE MENU OPTIONS ---------------- Select the option required either by using the keyboard up/down arrows or the mouse and then <ENTER> or by typing the first letter on the menu line. Note that throughout the program, options that require a single character do not need a line terminator. Typing ahead does not cause any problems as the input buffer is always cleared immediately prior to selection. An obvious yes/no choice requires a <Y> for 'yes', any other character or just <ENTER> for 'no'. Similarly the mouse keys may be used - the left mouse key represents <ENTER> and the right key represents <Y> or <ESC> as appropriate. When you have a multiple choice to make after the Main Menu, the options available will be displayed at the bottom of the screen. The program name, version, name of datafile in use, the printer selected and the date will always be displayed at the top of the screen. All the default settings are taken from the defaults file ACNET.DEF and the values as supplied will suit most applications. 6.1 Display Component Values ------------------------ This starts by showing the number of nodes defined and the input, output and common node numbers. Then all components, their allocated node numbers together with values and any further parameters will be displayed in an ordered sequence on the screen. If the data exceeds the screen length then use the arrow keys or the mouse to view the complete list. <ESC> returns you to the Main Menu. 6.2 Print Component Values ---------------------- The circuit values etc. will be printed via LPT1: in the same format as appeared on the screen above. If the printer is off line, the program will prompt you to switch it on or to abort printing. 6.3 Response of Circuit ------------------- Supply the required frequency value in Hz. Decimals may be used. You may add <k>,<M> or <G> to represent kHz, MHz or GHz but there must be no gap between the last digit and the letter. The response of the circuit at the given frequency will then be calculated and displayed showing :- (1) Gain in decibels (dB). A loss is indicated by a negative value. (2) Phase Shift between the defined input and output nodes in degrees. Values are only continuous in the range +180 to -180 degrees. (3) Modulus of the Input Impedance in Ohms or multiples thereof. (4) Modulus of the Output Impedance in Ohms. If the real part of either impedance is negative this will be indicated. Repeat for other frequencies as required. To obtain a printout, use the <PRINT SCREEN> key. <ESC> will return you to the Main Menu. Note that the mouse keys cannot be used to terminate numerical input. ACNET will calculate the response of a circuit at zero frequency provided there is a DC path between the input and output - otherwise errors will occur. E.g., NOTCH300 has a finite response at zero frequency whereas HPFILTER does not. 6.4 Change Component Values ----------------------- To input or to change existing component values the format is as follows :- COMPONENT SYMBOL PARAMETERS [Optional value(s)] --------- ------ ---------- RESISTOR R Node_1 Node_2 Resistor Value(Ohms) CAPACITOR C Node_1 Node_2 Capacitance Value(Farads) INDUCTOR L Node_1 Node_2 Inductor Value(Henries) [R(Ohms)] MUTUAL INDUCTOR M Pri_S Pri_F Sec_S Sec_F Lp(H) Ls(H) k [Rp(Ohms)] [Rs(Ohms)] TRANSFORMER T Pri_S Pri_F Sec_S Sec_F Ratio (1:n) BIPOLAR B Base_node Coll_node Emitter_node Beta Ic(A) TRANSISTOR [Ft(Hz)] [Cbc(F)] [Cbe(F)] [Cce(F)] FET F Gate_node Drain_node Source_node Gm(A/V) [Cgd(F)] [Cgs(F)] [Cds(F)] VALVE V Grid_node Anode_node Cathode_node Gm(A/V) Ra(Ohms) [Cga(F)] [Cgc(F)] [Cac(F)] OP-AMP A I/P+ I/P- O/P [Gain(dB)] [Zin(Ohms)] [f3dB(Hz)] The Op-amp common is circuit common node. Values are typed in at the * prompt. The usual component suffixes may be used ; i.e., p,n,u,m,k,M as appropriate. For example, a capacitor of value 6.8uF, an inductor of value 1.2mH with a series resistance of 0.1 Ohm and a resistor of 3.3kOhms all connected in parallel between nodes 3 & 4 would be input as :- * C 3 4 6.8u<ENTER> * L 3 4 1.2m 0.1<ENTER> * R 3 4 3.3k<ENTER> ( or * R 3 4 3300<ENTER>) Definition of the series resistance of both inductors and mutual inductors (Rp, Rs) is optional - if undefined by the user then a value of 1.0E-15 Ohms will be assumed. Similarly for transistor capacitances which will be set to 1pF, Ft to 300MHz and for op-amps the default gain would be 80dB, the input resistance 10MOhms and the cut off frequency (-3dB) would be set to 10MHz. Components in datafiles generated by earlier versions of ACNET where these optional values could not be defined will automatically have them set to the above default values. They can easily be changed. So a bipolar transistor (either NPN or PNP) with base connected to node 4, collector to node 7, emitter to node 9, with a current gain (Beta) of 200 and a collector current of 1.5 mA would be input as :- * B 4 7 9 200 1.5m<ENTER> The interelectrode capacitances would automatically be set to 1pF and Ft to 300MHz. However, if you wished to specify an Ft of 150MHz and capacitances of Cbc = 0.5pF, Cbe = 3.0pF and Cce = 10pF as well then this would be input as :- * B 4 7 9 200 1.5m 150M 0.5p 3.0p 10p<ENTER> Components can be typed in any order. If any component already exists, then its value will be changed to the latest value, which means that you cannot put components of the same type in parallel. Note that delimiters must be spaces. The nodes for two terminal networks can be given in either order. The backspace key may be used to correct input. Entering incorrect data will be indicated by a response of 'TYPING ERROR' and no change will take place. The suffixes are not case sensitive except where there is ambiguity as in the above example - 'm' and 'M'. You cannot type inappropriate letters as the range is restricted; E.g. only M for resistance and only m for inductance. To delete a particular component type the symbol, the node numbers and then <D>. E.g., to delete the above bipolar transistor you would type :- * B 4 7 9 D<ENTER> On entering the 'Change' mode, the datafile revision number is automatically updated - this will appear on the graph and component printouts. Having input/changed/deleted the values required, type <G> to go on. If the datafile is a new one, you will be prompted to define the input, output and common nodes. If an existing file was used then you may redefine these nodes if you wish. This allows you to calculate the response of any intermediate part of a circuit - you may, for example, choose a decoupling arm as the input node in order to ascertain its effectiveness. Note that the maximum node number is 50 (8 for the smaller versions of the program) with no restriction on the number of components. You cannot have an input/output/common node number greater than the highest component node number defined. If you ever have less than 3 nodes ACNET cannot calculate a result. 6.5 Open a Data File ---------------- Component details are stored in datafiles with a .DAT extension. The names of those already available will be displayed. The current datafile may be closed and another opened by means of the up/down/left/right arrow keys or by the mouse. Use F1 to create a new file (see below), F2 to make a copy with a new filename and F3 to delete a datafile. 6.5.1 Defining a New Circuit & Datafile --------------------------------- If you are starting with a new circuit, then you must number all the nodes (junctions) starting at 1 as shown in the example circuits. It does not matter how you organize the numbers, but there should be no gaps in the sequence. If you subsequently change the circuit and delete all connections to a node you must either reorganize the node numbers or you can leave the node unconnected - this will just slow down the analysis. All common (ground) connections must have the same node number. The power supply connections count as common, although you can allow for the supply source impedance. Do not set main component values to zero otherwise errors may occur. If you wish to join two nodes together without reorganising node numbers, use a small value resistor - say 0.1 Ohm. Having done this you must then create a new datafile. Select 'Open Data File' from Main Menu and then NEW_FILE by means of F1. Type the name of the new file required - the .DAT extension will be added automatically. You cannot type an illegal DOS filename. The new file will be created and you will then be prompted to supply an appropriate header message of up to 45 characters which will be displayed when you subsequently access the datafile. The revision no. of a new file will be set to 0. You must subsequently enter the 'Change Components' mode in order to define the circuit values. 6.6 Graph Plotting -------------- On selecting the graphplot facility, the Graph Menu will lead you to one of five further menus giving in total a choice from 60 preset frequency scales or a user defined scale. Select the one you require by using the arrow keys or the mouse. You have a choice of frequency range as indicated, covering from 0.003Hz up to 300MHz, over 1, 1.5, 2 or 3 decades and utilizing 80 or 132 columns. Having made your selection of frequency scale, press <ENTER> to continue. If you selected the user defined scale then you will first have to supply the start and finish frequencies required - on subsequent use of this scale new values may be defined or the previous frequency values can be reselected by just pressing <ENTER>. Naturally the finish frequency must be greater than the start frequency. Once the graph plot calculation has been initiated, progress will be indicated by a count, 5-79 or 5-131. You may abort and return to the main menu at any time by typing <ESC> ; there may be some delay with large circuits running on lesser PC's. Having completed the calculations, the screen will show the frequency range employed, the maximum and minimum amplitude values computed over the frequency range as well as the current graph parameters. You may optimize the graph plot parameters to fit the range of the response to be plotted. These parameters are :- 1) Graph Scale Default initially 20dB. Should be set to 4, 8, 12, 20, ----------- 40, 60 or 80dB (or any value divisible by 4). These values represent the approx. length of 40 printed lines. 2) Top of Graph Default initially +5dB. May be set within limits of ------------ +200 to -200dB. It is best to use multiples of 5 or 10. 3) No. of Lines Default initially 45 lines. May be set in range 1 to 86. ------------ 4) Superimpose Mode You may superimpose plots, but results can be slightly ---------------- confusing if graphs converge on the simpler two level plots. If the Superimpose facility is enabled, you may clear the plot array at any time. The array is cleared automatically if you change plot parameters or if you enter the 'Set Defaults' mode. 5) Enhanced Mode If enabled, graphplots are printed in emphasized or ------------- double print as appropriate for Epson/IBM printers. This facility is not available if the printer mode has been set to TXT. It is automatically operational for HP printers. Default values for the above are taken from the default file every time you open a datafile. Having set up the plotting parameters, you can still change these before proceeding if you wish. On continuing, the response will be displayed on the screen. You can examine all the plot area by using the arrow keys and also Pgup/Pgdn and Home/End in the usual way or you may use the mouse to move around the graph plot. <ESC> will allow you to continue and you can then elect to print the graph if you wish. The graph data will be stored in the subdirectory \GRFFILES using the data filename or a revised filename of your own choice. Whichever you choose, the graphfile will have the extension .TXT or .GRF or .ELX or .EFX or .IBM or .E24 or .HPK as determined by the printer setting which you chose as appropriate for your printer. You cannot change the extension when renaming the file and the default on initial startup will be .TXT. (For a description of the printer settings see the 'Set Defaults' option below). Finally, the full name and size of the graphfile will be displayed. Note that you cannot rename a file to itself, and if you use the data filename, subsequent graphfiles will always overwrite the previous graphfile. If you wish to have a revised plot with an alternative amplitude scale using the values already calculated, then there is provision to do this. Also, if the printer was off-line you may come back to print out in this way too. All of this should be obvious from the screen prompts. Finally use <ESC> to return to the main menu. You may then plot other graphs using an alternative frequency range or you may make component changes and plot more graphs using the Superimpose mode too if you wish - but obviously you cannot change either the frequency scale or the amplitude scale in any way if you are wishing to superimpose plots. N.B. Typing <ENTER> or an illegal character (e.g., a letter when a number is required) for any of the graphplot options will cause the default or the previously defined value to be used. If you type an incorrect numeric value, this will not be accepted and you will be prompted for another value. Also, if there are less than 3 nodes defined for the circuit the program will not run and you will be returned to the Main Menu. 6.7 Set Defaults ------------ The default settings for the last datafile used, the graph parameters, graph length, printer settings and the disk drive for data and graphfile storage are contained in the file ACNET.DEF. This is read every time you open a datafile. The Defaults Menu will display the current values and you may change most of these default values yourself. 6.7.1 Second Disk Drive - Designated second drive for data and graphfiles. ----------------- As installed only one drive is used as indicated by 'NIL'. The ability to designate a second drive enables users with only low capacity floppy drives to use two drives, as one disk will soon become full when using ACNET. By keeping the main program files on one drive and the data and graphfiles on the second, much more space may be used - in fact any number of disks can be used in the second drive for data and graphfiles. To use two drives, first install ACNET onto one drive (say A:) using INSTALL.BAT as already described and take the opportunity to become familiar with its operation. (If your drives have only 360K capacity then you will have to limit the number of files transferred and store the sample graphfiles on another disk). Then set Second Disk Drive to (say) B: to use this for data and graphfile storage (any drive A-Z may be used). The new directories will be generated on the second disk automatically. You will have to move any existing datafiles to the second drive yourself. Operation is much slower when using two floppy drives in this way. Do not delete the datafile directory \DATFILES set up by the main installation program as without this ACNET cannot start from the original default file settings. 6.7.2 Printer Type - Select the printer option appropriate to your ------------ printer. Briefly, these are as follows :- TXT : Two level plots using printable characters only. This will work on any standard text printer but you set the printer into condensed mode and appropriate line spacings yourself. Graphfiles produced with this setting have a .TXT extension. GRF : As above with the addition of Epson control codes to give improved line spacing, enlarged and underlined print as well as condensed and enhanced print if enabled. For use with older Epson printers (RX80 series) which cannot handle redefined characters. Graphfiles have a .GRF extension. ELX : Plots using four levels/character for use on 9 pin Epson standard printers including the LX range. Graphfiles have a .ELX extension. EFX : Plots using four levels/character for use on 9 pin FX Epson printers. Graphfiles have a .EFX extension. IBM : Plots using eight levels/character for use on the IBM Proprinter. Graphfiles have a .IBM extension. E24 : Plots using eight levels/character for use on 24 pin Epson standard printers. Graphfiles have a .E24 extension. HPK : Plots using eight levels/character for use on the Hewlett Packard DeskJet 500 range of printers. Graphfiles have a .HPK extension. 6.7.3 Graph Frequency Scale - Frequency range code used on entering the --------------------- graphplot routine. Values appear on menus and graphplots. Possible range 0 - 60. 6.7.4 Graph Amplitude Scale - Default graph scale setting. May be set --------------------- to 4, 8, 12, 20, 40, 60 or 80dB. 6.7.5 Top of Graph Scale - Default Top of graph setting. May be set to ------------------ any value from -200 to +200dB. 6.7.6 Number of Lines - Defines the number of lines used for the graph- --------------- plot. May be set to any value from 1 to 86. 6.7.7 Condensed Print - May be toggled ON or OFF. Used only with 132 --------------- column plots. Always ON with HP printers. 6.7.8 Enhanced Print - May be toggled ON or OFF. Gives better quality -------------- print. Always ON with HP printers. The same defaults file is employed whichever version of ACNET is used. If the defaults file becomes corrupted or even deleted, a new one with the original default values will automatically be regenerated. 6.8 Help Screen ----------- Displays this documentation. Use Up/Down, PgUp/PgDn and Home/End keys or the mouse as before and <ESC> to quit. 6.9 Quit ---- This will close the current datafile and return you to DOS. N.B. In the unlikely event of not being able to return to the Main Menu, try <CTRL><C> and <CTRL><BREAK> to return to DOS ; if this fails then you will have to reboot. Do not attempt this while the disk is being accessed in case datafiles become corrupted. 7. GRAPH PRINTING FROM DOS ----------------------- You will find that the multilevel plots give vastly improved quality and should be used if you have the appropriate printer. When you exit the simulator program the last graph generated will also be found in the GRFFILES directory with the appropriate file extension. The .TXT .GRF .ELX and .EFX graphs may be printed using the DOS PRINT command. The .IBM .E24 and .HPK variants are modified by PRINT. This can be avoided by using the TYPE command with redirection to the printer, which is already provided in GPRINT.BAT. For example, from \NET_V4 you would use :- PRINT GRFFILES\HPFILTER.GRF PRINT GRFFILES\GRAPHS.ELX TYPE GRFFILES\HPFILTER.E24 > LPT1: ... or GPRINT HPFILTER.E24 GPRINT GRAPHS.HPK Note that GPRINT automatically adds the path for you. The graph points are calculated using an accurate logarithmic frequency scale, the values being exact at 0.3, 3, 30, 300Hz ... etc. The remainder of the frequency intervals indicated on the graphs may have a small error due to the integer printing grid. The frequency range code is shown at the bottom of the graph preceded by '$' and followed by the graph file extension. The 132 column plots give a better representation as the natural slope of 20dB/decade produce straight lines, there being 40 frequency intervals per decade at this setting. 8. SAMPLE DATAFILES ---------------- The following datafiles are included in your package. Schematics for most of these are given in CIRCUITS.TXT and typical graphplots in GRAPHS.TXT/.GRF/ .ELX/.EFX/.IBM/.E24 and .HPK - print out the appropriate graphplots to see what can be done. Some of the circuits contain more than 8 nodes and so the response of these can only be computed with the 50 node version of ACNET. (1) HPFILTER is a simple three element high pass filter with a cut off frequency (-3dB) of 299Hz. The default graphplot settings suit this circuit well. Use the Superimpose mode and change R 1 2 from 0.2 Ohm to 1.0 and then 5.0 Ohms and note the changes in the response (as shown in the first graph example). Note that from Version 3 onwards the inductor and its series resistance can be combined into one element. (2) FBAMP2A is a simple two stage feedback amplifer with a gain of 30dB. The frequency response is 3dB down at 78Hz and 17.2kHz. You can determine the feedback factor by opening the loop and noting the increase in gain. Note that R 2 5 is made up of 330k in parallel with 22k giving 20.625k. (3) DUBTUNE is a mutually coupled double tuned circuit as would be employed in an i.f. amplifer. The response with coupling factors (k) ranging from 0.04 (overcoupled) to 0.0033 (undercoupled) are shown. A coupling factor of 0.0157 gives critical coupling - maximum bandwidth with a flat response. (4) BANDPASS is a simple Butterworth active filter centred on 12MHz. The circuit is taken from Electronics & Wireless World Dec 90, p1061. (5) GYRATOR2 is a unity gain third order Butterworth Generalised Immitance Converter (GIC) filter with a 40kHz cut off frequency. Taken from Electronics World + Wireless World Jan 95, p54. (6) NOTCH300 is a high Q circuit tuned accurately to 300.0Hz. Note a loss of over 140dB at the resonant frequency. (7) VALVEAMP is a simple common cathode triode amplifier. The bandwidth is extended by the addition of the 100uH inductor L 6 2. N.B. u=gm*Ra. (8) WHITEPNK is a filter to convert white noise to pink noise. It has a slope approximating to -3dB/octave over the range 10Hz to 40kHz. The circuit is taken from the Maplin magazine Electronics No.61 p53. The author claims an accuracy of 0.25dB over the frequency range ! (9) BAX4 is a Baxandall tone control circuit popular in audio amplifiers. This now has an FET input stage. The bass response is controlled by the potentiometer formed by R 15 16 & R 16 17 and the treble by R 10 11 & R 11 12. To vary the response change the ratio of the resistors keeping the sum constant at 100k and 25kOhms respectively. The example graph plots show the response with the tone controls in various positions - the Superimpose mode was used to obtain these plots. The power supply impedance (R 1 2) is also included in this example. (10) GRAPHEQ is a nine band audio graphic equalizer based on circuits given in the NSC Audio/Radio Handbook. (11) TVIFAMP3 is a 3 transistor TV IF amplifier with traps for sound and chroma sub-carriers, used by Number One Systems Ltd. in their advertisements for their circuit analysis software. ACNET gives results in good agreement with their published figures as can be seen from the graphplot supplied. This is a good example of where a user defined frequency scale is needed as the amplifier covers such a restricted frequency range. (12) VIDEO1&2 : VIDEO1 is a common emitter amplifier with a gain of 37.6dB and a bandwidth (-3dB) of 1.25MHz. VIDEO2 is the same amplifier in a cascode arrangement - same gain but with a bandwidth of 3.85MHz. (13) LINE is a distributed LC line of 47 T sections with C=200pF & L=2uH correctly terminated with its characteristic impedance Zo of 100 Ohms. Total delay is 0.94uS giving 360 degrees phase shift at 1.063MHz. The input impedance Zin is always 100 Ohms at any frequency up to about 15MHz. Zout is a function of frequency as the driving end of the line is not matched. Zout is zero at low frequencies but at 265,950Hz, where the line is a quarter of a wavelength long, the phase shift is 90 deg. and Zout reaches its first maximum. It is interesting to evaluate the line parameters at half, three quarters and unity wavelengths. Above about 15MHz the simple equations for Zo and the delay are no longer valid due to the finite number of sections. This circuit has the maximum of 50 nodes. On a 12MHz 286 (without coprocessor) the program takes 23 sec (real version) and 115 sec (extended version) for each frequency calculation. A 66MHz 486DX2 takes 1.6 sec for both the real and extended versions. It is primarily the number of nodes - not the number of components - that determines the calculation time. (14) RIAA is a magnetic cartridge equalisation amplifier giving bass boost of 20dB and treble cut of 20dB. The response is accurate to within 0.2dB of the RIAA standard. (15) CROSSOVR is a 3 way loudspeaker crossover network. Crossover frequencies are 200Hz and 4kHz and the Superimpose mode can be used to plot the three individual responses on one graph. By summing the three outputs you can obtain the combined response. You will find that introducing a 180 deg. phase shift in the mid band output (equivalent to reversing the speaker polarity) gives the most level response. 9. TESTING AND RUNTIME ERRORS -------------------------- ACNET is written in Borland Turbo Pascal (C) Ver 6.0. Full error checking is on continuously as this does not slow the program appreciably. Comprehensive testing has been carried out on a range of IBM compatible PCs running DOS 3.3, 5.0 & 6.2. Comparison of the results obtained using PCSPICE to analyse some of the circuits shows exact agreement with ACNET. The graphplot routines have been tested on an HP DeskJet 500 printer, on Epson LX400 and Texan/Kaga KP-810 printers for the 9 pin plots and on Epson LQ400 and Star LC24/10 for the 24 pin variants. The Star was also used to emulate the IBM Proprinter X24. If your Epson printer does not support the redefined character standard (up to and including ESC/P83) you will probably get one of the characters ;<=>?@ABC etc. in each plot position. If this is so you will have to select TXT or GRF mode (or obtain a better printer !). Note that printers may need revised DIP switch settings to enable redefined characters to be used and that some so called "Epson compatible" printers do not comply fully with the Epson standard. 10.1. MAIN CHANGES INCORPORATED IN VERSION 2 -------------------------------------- 1) Easy to use menus provided, with no type ahead errors. 2) Smaller stack used for ACNET.EXE thus reducing the memory requirements. 3) Graph plotting facilities considerably extended. 4) Provision of a defaults file which can be changed by the user. 5) The ability to use two disk drives if required. 10.2. MAIN CHANGES INCORPORATED IN VERSION 3 -------------------------------------- 1) The use of predefined multilevel symbols for graph plotting. 2) Improved models for inductors, transistors and op-amps. 3) Printing capabilities include IBM and HP DeskJet printers. (V3.2) 4) All screen displays now provided by ACNET instead of LIST.COM. (V3.2) 5) Change in address for registration. (V3.2) 10.3 MAIN CHANGES INCORPORATED IN VERSION 4 -------------------------------------- 1) Use of suffixes k,M,G,T,m,u,n and p as component value and frequency multipliers. 2) Use of the mouse to control the program. 3) Addition of Defaults Menus with much simplified printer selection. 4) Addition of thermionic valves on the component menu. 10.4 FUTURE DEVELOPMENT ------------------ Version 5 of the program is due to be completed next year. It is planned to have :- 1) Calculation of the square wave response of the circuit. 2) Improved graph presentation on the screen with the use of colour. Your suggestions for any other additions/improvements would be welcome. 11. REGISTRATION ------------ ACNET is issued as shareware. Author - Peter M. Montgomery Address - Downings Bells Hill Telephone - 01753 643384 Stoke Poges SLOUGH SL2 4EG (UK) Advice, subsequent revisions and copies of the full program which can handle larger circuits with up to 50 nodes can be obtained by registering with the author for a fee of 10 pounds sterling plus 2 pounds for postage if overseas. When registering it would be helpful if you would indicate (i) the version of ACNET that you are currently using and (ii) your source of supply. ACNET : Version 4.1 Copyright (C) 1991-95 P.M. Montgomery ----------------------------------------------------------- README(4).TXT 15/05/95