@F Adaptive Spectral Estimator User's Guide 4GAdaptive Spectral Estimator 5H Copyright (c) 1987, Wesley Hertel and Steven Seidl This program may be freely distributed so long as the program, resource code, documentation, author credits, and copyright notice remain together. This program is NOT in the public domain. GEM and AES are trademarks of Digital Research. ST is a trademark of Atari Corp. Major portions of this program were developed with GFA BASIC (distributed by Michtron) The authors of this program highly recommend GFA BASIC as several functions this program executes would have been to difficult/slow/inaccurate to include if not for this fine language. Page 1 Adaptive Spectral Estimator User's Guide 4G Introduction 5H Adaptive Spectral Estimator (further referred to as ASE) is a program that simulates the spectral characteristics of a described signal. This program will transform a time domain signal into the frequency domain. Unlike time-frequency transforms such as the FFT, this program does not sample a actual signal but instead generates the frequency domain characteristics from a hypothetical signal. Signals are described to the ASE in the form of signal descriptive parameters. You, the user may describe a signal of interest using the following descriptive characteristics/parameters: * Timebase (seconds, milliseconds, microseconds, nanoseconds) * Carrier (Hertz, Kilohertz, megahertz, Gigahertz) * Phase type (Absolute, Coherent, Differential, Random, Reference) * Amplitude (Volts) * Duration (dependent on Timebase setting) * Position (dependent on Timebase setting) * Phase (360 degrees) The above descriptive characteristics/parameters may be manipulated in a virtually unrestricted manner. Users of the FFT algorithm will appreciate the ability to create the spectrum of signals at RF frequency (with virtually unlimited resolution), and users who do not know anything about spectroscopy may find this program graphically interesting if nothing else. Version 1.0 of the ASE (not to be confused with AES) is a complete program, several non-selectable items appear on the main menu bar but are not necessary to operate the program. Although this version (1.0) suggests a infant product, in reality it would probably be more like version 1.0 x 10^3 if all developmental stages were included. Version 1.0 simply indicates how far along the program was when the authors decided to share their work. Why all the chatter on version numbers? The answer to that question depends upon the reception of this program. Wes and I have worked very hard to produce a very powerful program at a very reasonable price [VS03T free]. If there appears to be a need for this and other scientific applications on the ST computer, and proper inclusion of copyright notice is maintained, version 2.0 (just multiply by 1 thousand for current developmental version) will be released. To give you an idea of what is currently in the works, the following list of functions are being developed for integration to the ASE: * 3-D Ambiguity function - variable X, Y, and Z scales - view perspective adjustments * Time Domain Analysis Tools - Falling/Triggered Raster displays for I/O of data - Oscilloscope display - Graphic waveform manipulation Page 2 Adaptive Spectral Estimator User's Guide * High Resolution printer output * Log/Linear amplitude scaling (with reference amplitude lock) * Amplitude control enhancement for GID * Output compatibility with DIF and other formats * FFT routine (if somebody gives me a format for a digitizer file) Due to Memory constraints, some of the above may be in the form of integrated software, not part of ASE, but compatible where feasible. 4GRequirements 5HFor ASE to properly function you need: * Atari 520/1040 ST computer * Depending on version of ASE, a color or monochrome monitor * floppy/hard disk w/MASE or CASE program and resource files * All desk accessories removed from memory * A desire to learn Why MASE and CASE? These file names indicate which version of ASE you have. Due to memory constraints inflicted by very large matrix manipulations, a separate color (CASE) version and monochrome (MASE) version of the ASE were produced. This is also the reason for the 'no desk accessories in memory' requirement. You are warned that running this program with desk accessories in memory may have unpredictable side effects. Note this limitation really only applies to 520 ST users, 1 meger's shouldn't have to much problem with accessories in memory, but will find that even if you do, they are disabled during program execution. Both versions of the ASE run exactly the same as far as user interface goes. In some areas, the monochrome version has a advantage of increased resolution (notably the graphic input/output routines), but at a price in increased processing time. 4G Specifications 5H Accuracy: Better then 1 part per million Frequency range: DC to Light Amplitude range: 0 to 9999999 Volts Phase Deviation: 0 to 360 Degrees Duration range: 0 to 9999999 Seconds Position range: 0 to 9999999 Seconds 4G Limitations 5H Maximum number of signal descriptive segments: 512 Page 3 Adaptive Spectral Estimator User's Guide Maximum number of plotted graphic data points: 400 Maximum number of calculated data points: 512 4G Signal input/output device types 5H Input Devices A) Graphic signal input (G_Input) B) Keyboard signal input (Input Data) C) Disk file signal input (Load Data) Output Devices A) Graphic Signal Display (Graph) 1. Frequency vs Amplitude (Frequency) 2. Frequency vs Time (Discriminator) 3. Frequency vs Phase (Phase) 4. Tag (works with 1 and 2) (Tag) 5. Recalc (works with 1) (Recalc) B) Display Signal Data (Display) C) Print Signal Data (Print) D) Scaled Frequency vs Amplitude plot (Hardcopy) Note the commands for the above I/O routines are stated in brackets to the right of each I/O type. For more details see the reference section of this text. Currently the printer output (Print and Hardcopy) work only with Epson compatible type printers. If your printer can handle a regular screen dump from your ST, then you do not have any problem. Disk files created and read by this program are currently in ASCII format, this was originally for the purpose of debugging the source code of this program. You, however, may find them interesting to see how your Data Segments are seen by the calculation routines, and also may want to modify your signals with any ASCII mode word-processor. A complete guide to the format of these ASCII files will be uploaded as a appendix at a later time. Page 4 Adaptive Spectral Estimator User's Guide 4G Getting Started 5H Here is where the tutorial for this program will go!! Unfortunately Wes and myself are so involved with the development of this program that setting aside time to write a good tutorial on it's use has so far been nearly impossible. What follows is a couple of examples of how to operate the program sufficiently enough to get you experimenting. So boot your ASE in gear and follow these simple examples: 1. THE SPECTRUM OF A 1 USEC, 1 VOLT PULSE WITH A CARRIER OF 10 MHZ A. Select FREQ GLOBALS from the PARAMETER menu. B. Select MHZ for Frequency base, MICROSECOND for time base and COHERENT for Phase type. C. Select INPUT DATA from the OPTIONS menu. D. Enter '1' at the 'ENTER NUMBER OF SEGMENTS:' prompt. E. Select CONTIGUOUS from alert prompt. F. Enter '1' at the 'AMPLITUDE' prompt. G. Enter '1' at the 'DURATION' prompt. H. Enter '10' at the 'FREQUENCY' prompt. I. Select CALCULATE from the OPTIONS menu. J. Enter '200' at the 'ENTER NUMBER OF DATA POINTS' prompt. K. Enter '7' at the 'ENTER MINIMUM FREQUENCY' prompt. L. Enter '13' at the 'ENTER MAXIMUM FREQUENCY' prompt. M. Select 'GRAPH' from the OPTIONS menu. N. Select 'FREQUENCY' From the options box on the screens right side. O. Select 'TAG' from options box, move around screen, to quit tag mode press right mouse button. P. Select 'RECALC' from options box. Q. Select GRAPHIC CURSOR from alert prompt. R. Move cursor about 1 inch from left side of data display and press the left mouse button. S. Move cursor about 1 inch from right side of data display and press the left mouse button. T. Observe the bandwidth has now been narrowed (like a zoom function). U. Select 'PHASE' from the options box. V. Select 'DISCRIMINATOR' from the options box (note that with no frequency deviation, this will display a straight line). W. Select 'MAIN MENU' X. Select 'DISPLAY' from the OPTIONS menu. Y. Enter several keystrokes to scroll thru data. Z. Now wasn't that simple (I'm out of letters, or it would have been longer). Page 5 Adaptive Spectral Estimator User's Guide 4G Using the Graphics Input Device (GID) 5H Basically the GID will releave the user of entering steps C thru H listed above. What this routine adds in ease of use, it equally decreases in the flexibility and accuracy of signal descriptions. All segments are assumed to have a amplitude of 1 volt in this mode, frequencies are only accurate to 1/128th the total bandwidth for CASE and 1/256th the bandwidth for MASE. Phase specification is also lost in this mode, GID defaults all phase deviations as 0 degrees, this applies to REFERENCE, DIFFERENTIAL, AND ABSOLUTE phase types. COHERENT and RANDOM are of course not effected. Upon selection of G_Input the user is given several prompts. Before choosing this option, please think about your signal of interest as once you reply to the prompts, the only way to reset them is to exit and then reenter the G_Input routine. With all that said and done, you might ask why use GID if it's such a beasty. Well, try to enter 512 segments describing a chirp (Low to High linear frequency modulation) with the keyboard! To describe the chirp signal would take thousands of keystrokes, with GID, the same signal is a few mouse clicks away (draw a diagonal line). G I D +----------------------------------+ <- Freq max | /\ | Y | | B | | | A | A | | N | X | | D | I | | W | S | | I | | | D | | | T | | | H | | \/ | +----------------------------------+ <- Freq min <---- X axis (total duration) ---> (in timebase units) The above crude drawing should give you a idea of how the parameters that you give GID effect your signal. Before I go into a simple example of GID, several statements should be made. First, remember that GID has to obey the 512 segment rule too (Use Segment Sample mode!), we decided to keep linear sample mode in for the users who want the capability to analyze detailed complex signals in a minimum time. First time users please avoid this option. Secondly, keep the number of tick-marks on the X axis less then 10 until you get a feel for how it works. Page 6 Adaptive Spectral Estimator User's Guide This version of ASE does NOT protect the user from him/herself in the GID mode! GID is meant as a powerful time saver, we know of no other program that lets you "draw" a signal. If you try to use it like a drawing program (ala DEGAS) you will soon find that your in trouble. (DEGAS is a trademark of Batteries Included (I think), Great Job Tom Hudson and thanks for DElite) I don't claim to know proper legalize so please consider several proper names in this text as trademarks of somebody. 4G A GID Walk-Thru 5H Lets use the same simple signal as we did with keyboard input a page or two back. If you have not changed the global parameters you can omit steps A and B (reference the previous walk-thru instructions). A. Select G_INPUT from the options menu. B. Enter 20 for Maximum Frequency. C. Enter 0 for Minimum Frequency. (that gives you a 20 MHz BW with the carrier centered) D. Enter '1' for X-axis window (a 1 usec pulse remember). E. Enter '1' for number of X-axis tick marks (1 segment). F. Enter '4' for number of Y-axis tick marks (for your reference only) G. Select 'Line' from alert box for type of drawing. H. Select 'Draw' from options box. I. Point and click at far left and center of GID display. J. Point and click at far right and center of GID display. K. Note a horizontal line, and press right mouse button to exit. L. Select Create. M. Select SEGEMENT sample mode (USE THIS MODE ALWAYS UNTIL YOU ARE FAMILIAR WITH THIS PROGRAM!!!) N. Select Exit O. Repeat steps I thru Z as mentioned earlier. Seem like alot of effort for something that is supposed to make things easier? In the above case your exactly right! Now lets use GID for something a little more complicated (the signal that is, GID dosn't get any more difficult). Reenter G_Input again and lets make a multi-segment signal. A Repeat steps A thru C the same as before. B. Enter '10' instead of '1' for steps D and E. C. Repeat steps F thru H the same as before. D. Point and Click at the far left and UPPER corner of GID display. E. Point and Click at the far right and LOWER corner of GID Display. F. Note a Diagional line, press right mouse button to exit. G. Repeat steps L thru O as above. Page 7 Adaptive Spectral Estimator User's Guide What you have just created is a 10 segment pulse, sampled at 1 usec intervals. Each Sample should be a different frequency, and the spectrum should be totally different then previous examples which were virtually identical. Sampling takes place at the center of each tick mark with the starting position of each segment at the location of the tick mark. The far left area of GID is always Time=0 The other functions of GID displayed in the option box (CLEAR, ERASE, and EXIT are self explanatory. Notice so far that we have only used LINE type signal drawing, this is because of the segment type sampling. To see the effect of pixel drawing and linear sampling just plot a couple of dots on the screen (no more then 512) and make sure when you calculate the spectrum that your described bandwidth is adequate to include the majority of the spectral power distribution. Linear sampling will take considerably longer time to CREATE the signal file, this is a result of having to evaluate and calculate every point on the GID display. Remember, the more data samples you input to the calculation routine, the longer it will take to calculate. The last topic concerning GID is the time and frequency displays, and the segment counter. In the upper right corner of the GID window you will notice two labels (Time (timebase):, and Freq (freqbase):) these displays will indicate the values that will be assigned to any particular pixel point if it is sampled. The segment counter is located in the lower right corner of the GID window, and is used to indicate to the user how many segments were created during a sample. As Mentioned in the opening portion of this text, use the keyboard method to enter simple signal types. GID functions best as a "What If" type device for complicated signals where a general idea of what the spectral characteristics should be suffice. 4G On Your Own With ASE 5H The above text on ASE should not be considered a definitive tutorial on the operation of ASE. This program is very flexible and can be used to describe signal types such as RTZ, Barker Code, FSK, PSK, AM, and just about any other signal modulation type you dream up. The ASE works with negative as well as positive frequencies, The output is as accurate at 1,000,000 Hertz as it is at 1 Hertz. Page 8 Adaptive Spectral Estimator User's Guide 4G Reference Section 5H DESK MENU About Spectrum This option will indicate the current version number, authors, and copyright notice of ASE FILE MENU Load Data This option will load a signal descriptive file (SDF) from disk. You can proceed directly to the calculate function after loading a SDF. Save Data This option will save a signal descriptive file from memory for later use. Print Data This option will print the calculated spectral data of a signal. A SDF must have first been calculated before using this option. Quit Program This option will return you to the GEM desktop. OPTIONS MENU Data Input This option allows the user to enter a SDF thru the use of the keyboard, and is the preferred method of data entry. See also NOTES ON DATA ENTRY Calculate This option will calculate n data points derived from the SDF between two frequencies (f1 and f2). Where n <= 400, and f1 < f2. Display This option will display data derived from the calculate function. To scroll thru the signal data simply hit a key. Upon completion of viewing data you will be returned to the main menu bar. Page 9 Adaptive Spectral Estimator User's Guide 4G Reference Section 5H Graph This option presents a multi-function graphics display device. Available to the user are: Frequency, Discriminator, and Phase displays. The user may also manipulate the data in several ways while in this mode; Recalculate the spectral Bandwidth, number of data points, tag values, display reference grid-lines, and several other forms of manipulation. Use this mode to setup your display for the hardcopy routine. This mode will become second nature after experimentation. G_Input This option display the GID and associated prompts used in the graphic entry of signal data. Experiment to get a feel for it's use. Hardcopy This option will scale and print the Frequency vs Amplitude data of your SDF within the confines established in the calculate function. PARAMETERS Freq Globals This option will display a dialog box with several options. The user should choose a Time Base, Frequency Base, and a Phase Type. These choices will drastically effect your data. The time base and Frequency base parameters should not need any further explanation (they are used simply as a factor in all numerical input/output and calculations). Phase type is a bit more complicated and will effect not only your signal data, but the amount of data you have to enter to describe your signal. See Notes on Data entry for details. Page 10 Adaptive Spectral Estimator User's Guide 4G Reference Section Notes About Data entry 5H Time and Frequency Base The Time Base selected reflects the unit of measurement of which all data entered is proportional to. For instance, if a time base of microseconds (usec) is selected, when you enter the number 2.94, you are actually entering 2.94x10S0-6T, or 0.00000294. Likewise, if a frequency base of Kilohertz is selected, and you enter 75.014, you are actually entering 75.014x10S03T, or 75,014. The numbers above mean nothing except to illustrate the effect of time and frequency bases. The following is a chart to assist you in what the various units of measurement mean: TIME: NAME ENG. NOTATION DECIMAL BASE SECONDS (sec) 1X10S01T 1.0 MICROSECONDS (msec) 1x10S0-3T .001 MICROSECONDS (usec) 1x10S0-6T .000001 NANOSECONDS (nsec) 1x10S0-9T .000000001 FREQUENCY NAME ENG. NOTATION DECIMAL BASE HERTZ (Hz) 1x10S01T 1.0 KILOHERTZ (KHz) 1x10S03T 1000.0 MEGAHERTZ (MHz) 1x10S06T 1000000.0 GIGAHERTZ (GHz) 1x10S09T 1000000000.0 PHASE TYPES The selection of phase type is a bit more involved then that of the time and frequency base. The following descriptions should help you establish which phase type you should select for proper spectral output. Coherent Signal phase is generated from a single RF source whose frequency is the same as the pulse (data segment). Initial phase is 0 at t=0. This type of phase is calculated without user intervention, and is the default for the program. Differential Signal phase is specified by the user in degrees (0-360). The entered amount of phase is the deviation from the previous segments ending phase. This selection is useful in simulating Phase Shift Page 11 Adaptive Spectral Estimator User's Guide 4G Reference Section 5H Keying (PSK) signals. Absolute Signal phase is expressed in absolute terms irrespective of any other reference or segment (what you enter is what you get (GIGO)). Random Signal phase is generated +/- 180 degrees randomly at start of each segment. No user intervention is necessary or possible. Reference Signal phase is +/- amount specified with respect to an RF source whose frequency is the same as the pulse segment and whose initial phase is 0 at t=0. COMMENTS ON ASE The authors of this program feel that the ASE is a step in the right direction for making the Atari ST computers presence felt in the scientific community. Future versions of ASE and other applications will be released at no cost to the public (although some may still be copyrighted) only if there appears to be a need for this type of application. How will we know this? The answer to that question must be answered by you, the user. If you like this program, or would like to make suggestions/comments for implementation into future versions, LET US KNOW!. We believe that there has to be some other Engineers/Technicians/Teachers/Whatever out there whom in their infinite wisdom, selected the ST for it's power/price performance ratio. Lets get together and make some serious scientific applications for this computer. The fact is that scientific/technical programs (e.g. MathCadS0TMT, and the like) will probably never be published for the ST because of the relatively small user base (compared to big blue). That leaves the development of these type applications to us, so far I have yet to see anything more technical then fractals (pretty and interesting, but no real application) for the ST. Lets see some good applications on subjects like Electronics, Astronomy, Photography, ect... . Please send your comments to the authors of this program via E-Mail. My UID on CIS is 72467,1242 or for GENIE . P.S. IF SOMEBODY OUT THERE HAS A USER ACCOUNT ON BYTE-NET OR BIX, PLEASE UPLOAD A VERSION OF ASE (MASE AND/OR CASE). WE REQUEST THIS AS BYTE CARRIES ARTICLES ON FFT/SPECTAL ANALYSIS FROM TIME TO TIME, AND PROBABLY HAVE A FEW EXPERTS IN SPECTROSCOPY THERE TO TEST THIS PROGRAM FOR ANY PROBLEMS THAT WE MAY HAVE MISSED. Page 12