ASP4.TXT

                    A.S.P. Version 4.00 (C) 1989-1996
                      AMPLIFIER SIMULATION PROGRAM


                     Written by KD9JQ  Charles H. Reichert
              955 Concord Lane   Hoffman Estates, Il. 60195

                           All Rights Reserved   

                              INTRODUCTION

    This program designs single stage common emitter or common source transistor
amplifiers used for narrow band weak signal service.  Many combinations of
design are easily obtained by use of different Automatic or Interactive Design
Routines.  The main goal of this program is to provide functional amplifiers
for Radio Communications.

    For the Contest minded person, a Utility program has been provided to "zero"
in on that optimum operating condition for maximum gain and minimum noise figure
of a particular device.  The designer is reminded that although this design may
be possible with resistive 50 ohm loads, it may not work in the real world.

    Although originally designed for FET, GaAsFET's, IGFET devices, the program
will work with Bipolars.  This program currently does not handle Large Signal
devices.  Some small signal devices with low input/output impedances may look
like Large Signal devices to the optimization routines N1 - N6 and may cause
some inaccuracies.  The Y4 option can be used as an alternative!

    Results of the program and the actual amplifier can vary if proper layout
techniques are not adhered to!  Numerous test amplifiers using the following
transistors have yielded close correlation to the program;

        MRF904   3N211   3SK124  3SK205

    Through use of this program the you will quickly gain insight as to how to
properly design an Amplifier, even if one is not schooled in Transistor Design.
The documentation will contain some personal insights on how to vary design
parameters to meet different user criterias.





















                                 Pg. 2
			   
                             DOCUMENTATION

The Program Window will first pop up.  Press Return F1 for the Device Library,
F2 to make a Data File for a new device and F3 for a schematic representation of
the Matching Circuits for the user to select from.
Enter the device file name (.DAT extension assumed) desired.  A wrong entry or
incorrect path will cause an Error routine to pop up.  You have the option of
trying again or exiting the program.  Make sure the DAT.CFG file has the path
for the .DAT files. The DAT.CFG file must be in the directory where the
.EXE files reside.  Once the selection has been made the Main Menu will pop up.

MAIN MENU Selections

    The Main Menu contains selections for Automatic and Interactive routines,
    Utilities, Device Configuration, Device Selection, and New File Creation 
    utility.

Auto Design Routines N1 - N6

    These routines make it easy for the non-technical person to design a
    pre-amp and evaluate different transistors real fast.  Pressing the F10 key
    while the cursor is on the routine of interest will provide a popup Help
    Screen which gives information on that routine.

    QL's are adjusted automatically during these optimizations to insure
    positive values of CT.  QL, QU, and Kc are reset to their optimized values 
    each time a new device is run.  They can be varied during the active
    routine with the F3 key.

    When YL (Real) and/or YS (Real) are < ZL or ZS the matching circuit
    automatically defaults to LO-Z Matching.  Losses are included in the 
    calculations.

"N1" This Option Optimizes for High Gain and Low Output VSWR while Optimizing 
    for Low Noise Figure. 

    Minimum Noise and High Gain usually occur at low values of Stern's Stability
    Factor K.  This routine will sweep a range of K while checking for minimum
    noise figure.
   
    The designer should be aware that not all devices will provide useable L/C
    values for the matching circuits at this value of K.


"N2" This Option Optimizes for High Power Out and Low Output VSWR while 
    Optimizing for Low Noise Figure. 

    YL (Real) is adjusted for Highest Output Power (dBm) while YL (Imaginary)
    is constantly re-adjusted for Lowest Output VSWR while YS (Real) is
    optimized for Lowest Noise Figure while constantly re-adjusting
    YS (Imaginary) for Input Reactive Match. The Input is not optimized for
    Lowest Input VSWR but for lowest losses since Lowest Noise Figure is what
    is desired.
	
    The Output Power is calculated as Linear Class B Output Power which is less 
    than or equal to the -1 dB compression point.


                                 Pg. 3

"N3" This Option Optimizes YL for a specified GT while Optimizing    
    Output VSWR and Noise Figure.  This option most useful for FET devices.

    The Caculated Gain will be within .1 dB of the User Specified Gain.
    YL (Real) is adjusted to the specified gain while YL (Imaginary) is
    adjusted for Lowest Output VSWR while Input YS (Real) and YS (Imaginary)
    are adjusted for Lowest Noise Figure.

"N4" This Option Optimizes Input/Output VSWR at a Designer specified GT.
    NF and PO are not optimized.  This option most useful for FET devices
    and Interstage Amplifiers where Noise Figure is not critical.

    The Caculated Gain will be within .1 dB of the User Specified Gain.
    YL (Real) and YL (Imaginary) are adjusted for Lowest Output VSWR
    while Input YS (Real) and YS (Imaginary) are also adjusted for the Lowest
    INPUT VSWR.

"N5" This Routine allows the user specify a design to a specific Stern's 
    Stability Factor K.  When first selected, the routine asks the user for a 
    new K.  K is made larger than the desired during the optimization if it is
    found the GS < Gin and/or GL < Gout.  This will allow realistic QL's and
    low VSWR's.  

    Output VSWR is optimized in this routine.

"N6" This option works just like N5 except Input VSWR is also optimized.
    K is made larger than the desired during the optimization if it is
    found the GS < Gin and/or GL < Gout.  This will allow realistic QL's and
    low VSWR's.  The Input and Output VSWR's are optimized in this routine.

Interactive Routines Y1 - Y4

    Stern's Stability Factor K can not be changed from the default value for
    Y1 - Y4 options.  These are user interactive routines and the K is
    determined by the user YS and/or YL.

    QL, QU, and Kc can be varied during the active routine by use of the F3 key.
    QL's are not adjusted automatically in the Y2 - Y4 routines except QL(input)
    of the  Y1 routine.

    When YL (Real) and/or YS (Real) (Y2 - Y4) or just YS(Real) (Y1) are
    < ZL or ZS the matching circuit automatically defaults to LO-Z Matching. 

"Y1"  This Option lets the Designer enter a user specified Tranformer 
    of known transformation and reactive component.  The Input is optimized 
    for Best Noise Figure and the Output for VSWR.

    QU (Output) should be adjusted to the measured value after the first run.
    QL (Input) is adjusted automatically during the optimization to insure
    positive values of CT.  QL (Output) will automatically be calculated during
    the run and will be < 1 for most broadband applications.  A Coefficient of
    Coupling = 1 for Kc is used for the Transformer.  The program will return to the 
    default values when selecting a routine other than Y1.





                                 Pg. 4

"Y2" This Option accepts the Designers specified YL (Real), calculates
    GT while Optimizing for Low Output VSWR and Lowest Noise Figure.

    This routine is useful if the designer just wants to see the effects
    of manually varying the Load while maintaining a Low VSWR output and
    Lowest Noise Figure for this Load.  The SR routine will do the same by
    sweeping a range of Loads at one time but with a given Reactive component
    of the Load.

"Y3" This Option lets the Designer enter a user specified YL while the
    input is optimized for Best Noise Figure.

    This routine is useful if the designer wants to see the effects of
    different YL's (Real & Imaginary).  Output is not optimized for Low
    VSWR.

"Y4" This Option lets the Designer enter a user specified YS (Real & Imaginary)
    and YL (Real & Imaginary) in order to customize the amplifier.

    The Input is not optimized for Best Noise Figure and the Output is not
    optimized for Low VSWR in this selection.

    If N4 Source and Load Admittances are used for Y4, the Gain will be 
    somewhat higher and the NF reading much lower because in the N4 option 
    an input Shunt resistor is used which adds to the circuit losses.
    The Y4 option assumes YS is a pure source except for Inductor losses.
							 
Utility Routines

"SI" This Utility will sweep a range of YL(Img) while keeping YL(Real) 
    fixed. YS(Re & Img), NF, GT, and PO are displayed.  Uses default Q's, 
    Kc's, and K.

    The Status column will indicate OK for Stable and ** for Unsafe conditions.
    For Unsafe conditions the ** will indicate different colors for different
    degrees of instability defined as;

        K > 1   Stable                - Cyan
	Input Gin is negative only    - Yellow
	Output Gout is negative only  - Blue
	Gin & Gout are both negative  - Violet
        Gin, Gout are negative, K < 1 - Red

"SR" This Utility will sweep a range of YL(Real) while keeping YL(Img) 
    fixed. YS(Re & Img), NF, GT, and PO are displayed.  Uses default Q's, 
    Kc's, and K.

    The Status Column will indicate different colors for different conditions.

        K > 1   Stable                - Cyan
	Input Gin is negative only    - Yellow
	Output Gout is negative only  - Blue
	Gin & Gout are both negative  - Violet
        Gin, Gout are negative, K < 1 - Red  
	



                                 Pg. 5

"SZ" This Utility allows the Designer to change the Real values of the
    Source (ZS) and the Load (ZL).  The user has the option of four (4)
    different 50 Ohm / 75 Ohm ZS/ZL combinations to work with.  This will
    allow use of low loss 75 Ohm cable.  75 Ohm useful for Cable TV.

"DD"  This selection will redisplay the Data just calculated if no other
    selection has been made.  There will be no data screen to view if no
    previous selection was made.

"DP" This selection will display the S and Y Parameters of the Device.

"PI" This selection will display useful information about the program.

                 SPECIAL DATA DISPLAY FUNCTION KEYS

Shift F1 (^F1) This will send the Data Output Screen information to the Printer.

Left Arrow
    This will Toggle back and forth between the Capacitive Coupling Matching
    Circuit and the Tapped Inductor Circuit for the Input Network. 

Right Arrow
    This will Toggle back and forth between the Capacitive Coupling Matching
    Circuit and the Tapped Inductor Circuit for the Output Network. 

F2  This selection pops up a window showing the Input/Ouput Matching Limits
    for transformed Sources/Loads and the Mis-Match Ratio for for the current 
    Stern's Stability Factor.  Also Maximum Safe values of the Transformed
    Source are given for Schottky and Silicon diode Front End protection 
    for given device parameters.

F3  Pressing this Key will display the current Input/Output Inductor UnLoaded/
    Loaded Q's and their Coefficient of Coupling (Kc), Operationg Fo along with
    Stern's Stability Factor.  The Unloaded Q's and Kc's can be altered at this
    stage and the Configuration file updated.  The operating frequency Fo and
    Loaded Q's can be changed during the design process but will not change the
    configuration file.  K is shown for informational purposes only.

    To change values, just enter the selection number, (CR), and type in the
    new value.  When finished press the Esc Key to redisplay the new parameters. 
    If you make a mistake while entering just press the BKSP Key and re-enter
    the correct value. 

F4  Pressing this key activates the plotting routine.  Input/Output tuning 
    component values can be varied by the user by pressing the F1 key 
    (Plot Routine) to further optimize the circuit with visual feedback.  

    Amplifier Stability, Gain, NF, and Output VSWR are displayed.

    Plotting is done at a medium sweep rate and sweep range.  Faster/Slower 
    sweep rates as well as Wider/Narrower sweep ranges can be selected by the
    F10 key.  

    Pressing F8 will return the user to the main program where the last YL, YS 
    was used in the Screen Plot Utility.  The Y4 routine is used to document the
    design.

    No Plotter/Printer Drivers are currently available for the Screen Plot.
                                 Pg. 6

                    DEFINITION OF DISPLAY SYMBOLS                   

        YS = Source Admittance and Susceptance  "Enter as 1/GS, 1/BS"                     
        YL = Load   Admittance and Susceptance  "Enter as 1/GL, 1/BL"                     
        YI = Device Input  Admittance and Susceptance  "Shown as 1/GI, 1/BI"               
        YO = Device Output Admittance and Susceptance  "Shown as 1/GO, 1/BO"
        GT = Device Gain (dB) including Losses                      
        NF = Device Spot Noise Figure (dB) including Input Losses   
        PO = Maximum Linear Output Power (dBm)                      
         K = Stern's Stability Factor at Operating Frequency
      LOSS = Total Amplifier Losses (dB) "Inductor, RSH Losses"
        TS = Amplifier Tuning Sensitivity   < .3 is not Critical    
        CT = Capacitance required to resonate Tuned Circuit
        Cc = Series Coupling Capacitance required for proper Source 
             or Load Transformation 
        LT = Parallel Inductance needed for chosen Loaded Q and Load
         N = Inductor Turns Ratio for Inductor to provide proper    
             Source or Load Transformation.  #Turns (Length) * 1/N  
        QU = Unloaded Inductor Quality Factor  User Settable       
        QL = Loaded Inductor Quality Factor    User Settable        
        RS = Transformed Source from 50 Ohms                        
        RL = Transformed Load from 50 Ohms                          
       RSH = Shunt Resistance required for 1:1 VSWR                 
        Kc = Inductor Coefficient of Coupling  Provides correct N (Tap point)
             User Settable - approxomately .3 for airwound, .9 for toroids        
        ZI = Impedance looking into the Amplifier                   
        ZO = Impedance out of the Amplifier                         
        ZS = Source Impedance - 50 or 75 ohms Resistive - Selectable
        ZL = Load Impedance - 50 or 75 ohms Resistive   - Selectable
        L1 = LO-Z Match Shunt Inductor - Device Port to RF Ground        
        C1 = LO-Z Match Series Capacitor - Device Port to L2 Series Inductor    
        L2 = LO-Z Match Series Inductor - From Series C1 to In/Output Port      
        C2 = LO-Z Match Shunt Capacitor - In/Output Port to RF Ground  

ESC This Selection returns to the Main Menu.
					  

                            MATCHING methods

Capacitor Coupling Symbol Definitions

    CT = Capacitance required to resonate circuit with LT.
    Cc = Series coupling capacitance to top of LT required to transform
         the 50 ohm or 75 ohm line up to the required RS or RL.
    LT = Inductance required for a particular Fo and QL.

Inductive Tap Method

    CT = Capacitance required to resonate circuit with LT.
    LT = Inductance required for a particular Fo and QL.
         N = Turns Ratio - use 1/N * # Turns for Tap.







                                Pg. 7

LO-Z Matching Method
    This Method is utilized when the transformed Load falls below
    the ZS or ZL selected.  Inductor Losses are included when calculating
    Gain, NF, VSWR, etc.

    L1 = LO-Z Match Shunt Inductor - Device Port to RF Ground     
    C1 = LO-Z Match Series Capacitor - Device Port to L2 Series Inductor    
    L2 = LO-Z Match Series Inductor - From Series C1 to In/Output Port
    C2 = LO-Z Match Shunt Capacitor - In/Output Port to RF Ground  

    See Motorola (TM) RF Device Data Manual DL110 Rev 3 Pg 7-30     
               Application Note AN267  Network C1                   

BroadBand Transformer
    The Turns Ratio "N" is calculated from the given transformed RL and BL
    using a default Kc of 1.  After the first run of Y1, modify Q unloaded
    (F3 Key) to the actual measured value.  Q Loaded is automatically
    calculated.

Misc. circuits
    The designer need not be limited to the above matching circuits.
    With the YL, YS, YI, and YO provided, other circuits such as
    micro-strip can be utilized. 

    Biasing methods of the transistors are left to the designer.


                               DESIGN AIDS

    Q's are adjusted in the N1 - N6 and Y1 Routines to automatically provide
    real values of CT.  In the Y2 - Y4 Routines, if CT and/or Cc are negative,
    then a higher value of QL must be used. 

    The Inductance values of LT can also be varied to a desired or measured
    value by changing QL if QL is above the minimum value calculated during
    the N1 - N6 and Y1 Routines.
								   
    Fo can also be varied to a particular operating frequency if within 10%
    of the original data file Fo.

    The turns ratio N has been corrected for the Coefficient of Coupling Kc.

    Excessively high N at the Input could cause device failure even if shunt
    back-to-back protection diodes are used if the voltage step up exceeds the
    device gate to source breakdown.  Check the Vendor's data sheet for device
    maximum ratings.  For Schottky diodes use Vgate =.6V * N +/- Vsource (Volts),
    for Switching diodes use Vgate = 1V * N +/- Vsource (Volts).

    In general Capacitive coupling will yield lower VSWRs while the Inductor
    Tap will provide lower input losses. 

    Use chip capacitors and resistors if possible.  Insure good shielding and
    grounding.  Orient Inductors at right angles to each other even with using
    shielding.  Use feedthru caps for Supply feeds.  Use low loss BNC or SMA
    type connectors.  Use double sided solder plated copper PC Boards with
    grounds tied together at numerous spots to provide low ground impedances.  


                                 Pg. 8

New File Creation Utility
    A window will pop up asking you if you want to enter S-Parameters or
Y-Parameters.  Enter the letter S or Y.

    The program will then prompt you with a series of questions pertaining to 
the device you are using.  All questions should be fairly self explanatory, but
if you are not familiar with transistor design at all, then refer to the 
following detailed explanations.  At the end of the questions you will be 
queried as to whether you want to write these entries to a new data file.

    Making a new data file will allow you to call up the device directly
from the Data Library without re-entering all the parameters again.  Make sure
you specify a file name not already used.  The Data Library will be displayed
at this time in order to show you the current names of the files.  The .DAT
extension is automatically added when you make a new file. 

(1) Enter Device Part Number

    Enter the Device Part Number only <CR>  (DOS limit of 8 characters)

(2) Specify Device Type <CR>

    BI for Bipolar Junction Transistor
    JF for Junction FET
    SG for Enhancement Mode Single Gate FET
    DG for Enhancement Mode Dual Gate FET
    GF for Single or Dual Gate GaAs FET

(3) What is VDS or VCE (Volts)

    Enter Device operating Drain/Source or Collector/Emitter Voltage <CR>

(4) Specify Operating Frequency (MHZ)

    Enter Device operating Frequency <CR>

(5) Specify NF (dB) measured in a 50 Ohm system (Bipolars Only)

    Enter the Noise Figure of the BJT as indicated by the Vendors S-Parameter
    DATA Sheet <CR>.   This will be the Un-optimized value at some frequency. 
    Example:  1.6 dB at 500 MHZ for the Motorola (TM) MRF-904 Device

(6) Specify Frequency (Mhz) that the NF was measured at (Bipolars Only)

    Enter the frequency of the BJT where the un-optimized Noise Figure
    was measured <CR>
    Example:  500 MHZ for the Motorola (TM) MRF-904 Device

(7) Specify IDss for FET Devices or Continuous IC for Bipolar (mA)

    Enter the Short Circuit Drain Current or Maximum Collector Current of the
    Device. <CR>
	
(8) Specify Operating ID or IC (mA) for Device

    Enter the operating Drain or Collector Current of the Device <CR>


                                 Pg. 10

(9) Specify Device VGS1 or VBE Reverse Breakdown Voltage (Volts)

(10) Specify Device VGS1 or VBE Operating Voltage

(11) Specify HFE (Bipolar Only)

    Enter the Bipolar HFE from the Vendor Data sheet <CR>

(12) Specify FT (MHZ) (Bipolar Only)

    Enter the Bipolar FT from the Vendor Data sheet <CR>

(13) Is Data Input Correct? (N)

    Enter " Y " if OK then <CR> else just <CR> to re-enter all previous data.

           Device S-Parameter Data Entry from Vendor Data Sheet
           @ Device Operating Frequency and Bias Conditions

    * The Y-Parameters follow the same sequence except that you are entering
      Admittances.

(14) SPECIFY S11(M), S11(P)

    Enter S11 Input Reflection Coefficient <CR>
    Enter S11 Phase Angle (Degrees) <CR>

(15) SPECIFY S21(M), S21(P)

    Enter S21 Forward Reflection Coefficient <CR>
    Enter S21 Phase Angle (Degrees) <CR>

(16) SPECIFY S12(M), S12(P)

    Enter S12 Reverse Reflection Coefficient <CR>
    Enter S12 Phase Angle (Degrees) <CR>

(17) SPECIFY S22(M), S22(P)

    Enter S22 Output Reflection Coefficient <CR>
    Enter S22 Phase Angle (Degrees) <CR>

(18) Is S-Parameter Data Correct? (Y)

    If Data is correct press <CR> else type " N " <CR> and re-enter Data

(19) Do you wish to make this entry a Data File? (Y)

    Enter <CR> for "Y" or " N " <CR> for "No"

    ** Caution **  If you select " N "
    Program will still retain the entered data while the program is still
    running but will loose it if a different device is entered or you exit
    the program.




                                 Pg. 11

(20) If you pressed Y then enter Data File Name 
     (.DAT extension added automatically)

    If you previously answered yes then this prompt will display itself.
    Enter the Data File name (Normal DOS limits) and press <CR>
    The file will be written to the Path indicated by the DAT.CFG File

    ** Caution **
    If you use a name previously used the old file will be written over!

(21) You will be asked if you what to generate another file or return to
    program.  Enter your response.

                           SCREEN PLOTTING ROUTINE

    The Screen Plotting Routine allows a visual display of Amplifier Gain,
    Stability, N.F., and Output VSWR.  The designer can tweak the matching 
    circuits for optimum performance.  EGA or higher graphics are required
    to run this routine.

    Current YS and YL, along with Center Frequency Gain, N,F., and VSWR 
    are values are also shown. A Stability Color Coded Bar is displayed
    at the bottom of the plot as well as the 3dB Bandwidth at the top.

                                  UTILITIES

^F1 GRAPHICS SCREEN DUMP
    Pressing "SHIFT + F1" will provide a B&W Graphics Screen Dump to your
    graphics capable printer.   Since the standard DOS GRAPHICS.COM doesn't 
    allow the user any flexibility a user configurable file DISPLAY.CFG has
    been provided to allow customizing of the Screen Dump format to your 
    particular printer.

F1  TUNE 
    Pressing F1 pops up a screen containing the Input and Ouput 
    Matching Components.  Values can be modified to change performance.

    Changing the Output CT provides the best choice in adjusting the
    N.F. without degrading amplifier performance to a large degree.

    Loaded Q's are automatically recalculated when changing inductor values
    or Source, Load changes.

F4  MENU
    Returns to Main Program Menu.  Amplifier Data is not saved.

F8  DOCUMENTATION
    Returns Modified or Un-Modified Amplifier Design to Main Program.
    routine Y4 is used to reconstruct the circuit except for Y1 in which the
    Y1 routine is used.

F10 CFG
    The Plot Utility is normally set to the medium plotting speed and 
    Mid-Range on frequency sweep.

    Plotting speed (or Line density) can be changed and the sweep reset
    to a larger or smaller range.