to quantify D/A converter imperfections, it is almost impossible
to reflect these quantities to the DDS output and determine spectral purity. So, al-
though these measures provide some evaluations guidelines for DACs, normally DDS
spectral purity with a specific DAC must be evaluated on a case-by-case basis. A
thorough introduction to this important aspect of DDS design can be found in [14-
17].
7.3.7 Spurious Suppression in Direct Digital Synthesizers Using Numerical
Techniques
Additional digital techniques may be incorporated into the generic DDS in order
to quantify D/A converter imperfections, it is almost impossible K reflectthese quanitities to the DDS output and determine spectral purity. So, al- gxugh these measures providesome evaluations guidelines for DACs, normally DDS pectral purity with a specific DAC must be evaluated on a case-by-case basis. A thorough introduction to this important aspect of DDS design can be found in [14- 7) 7.3.7Spurious Suppression in Direct Digital Synthesizers Using Numerical Techniques Additional digital techniques may be incorporated into the generic DDS in order to
DDS simulator self test
Runs the ATmega8 headless (no audio device) and checks it against what program/avr/da-test.asm says it must do.
stock - ISR every 25 cycles = 262144 Hz
PASS stock: LCD line 1 after
SONY DGD150P DATA CARTRIDGE CARTOUCHE DE DONNEES FUJIFILM DC3-125 TDK DC4120 4mm DATA CARTRIDGE SONY DDS DATA CARTRIDGE DDS CARTOUCHE DE DONNEES DGD150P Media Recognition System
Sagezahn
01000,0 Hz
BEDIENUNG
--
-
+
++
~
GROB AB
FEIN AB
FEIN AUF
GROB AUF
FORM
Power off
20 kHz Bessel-Tiefpass
Pegel
R-2R-Leiter, ungefiltert
nach Bessel-Filter
4.00 ms F
FREQUENZ
1000.0 Hz
SIGNALFORM
Sagezahn
ECHTZEIT
3.5x
Tasten: Z -- X -- C + V ++ Leertaste Signalform
; ; =========================================================================== ; dds-seq.asm - Schrittsequenzer fuer den ATmega8-Funktionsgenerator von 2003 ; ; Eigenstaendige Quelle. Der Generator von damals (Wellenformtaste, vier ; Stimmtasten, Frequenzanzeige) ist hier nicht mehr
; Digitaler Funktionsgenerator für Sinus, Rechteck, Dreieck und Sägezahn ; ; Copyright (C) 2003 Andreas Schwarz <andreas-s@web.de> ; ; This program is free software; you can redistribute it and/or ; modify it under the terms of the GNU General Public License ; as published by the Free Software Foundation; either version 2 ; of the License, or (at your option) any later version. ; ; This program is distributed in the hope that it will be useful, ; but WITHOUT ANY WARRANTY; without even the implied warranty of ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ; GNU General Public License
DDS simulator self test
Runs the ATmega8 headless (no audio device) and checks it against what programm/avr/da-test.asm says it must do.
stock = ISR every 25 cycles = 262144 Hz
PASS stock: LCD line 1 after
Elektronik Ernst Schmidt DDS Signalgeneratoren praktisch aufbauen und anwenden FRANZIS Das Verfahren der Direkten Digitalen Synthese (Direct Digital Synthesis - DDS) in der Praxis C++ Programmierung 470 praxisnahe Übungen mit Lösungen
ANZEIGE Saegezahn 01000,0 Hz AUSGANG R-2R-Leiter, ungefiltert - nach Bessel-Filter 4.00 ms Fenster BEDIENUNG GROB AB FEIN AB FEIN AUF GROB AUF FORM Power off FREQUENZ 1000.0 Hz Signalform 3.5x MCU-Takte 158.5 M Tasten: Z --- X --- C + V ++ Leertaste Signalform. Gedrückt halten wiederholt, wie am echten Gerät.
to a 720 TTL * negative voltage below - 1.25 V. 2N5640 1.0 k Control V V R 1 ref R2 ref Omax + DSS DDS Minimum V out 1.25 V V SS V O BV DSS+ 1.25 V + SS, ILmin- DSS < O < 1.5 A. * 1 protects the device during an input short circuit. As shown 0 < O < 1.0 A. Figure 21. Adjustable Current Limiter Figure
components, but can be extended to include special purpose digital chips. Direct digital synthesis, DDS, is briefly presented and emphasizes the basic character of the function that will generate spurious outputs. A measured example is presented. 4.8—The Ugly Weekender, MK-II, A 7-MHz VFO Transmitter:
t-Menü u (Drucken) ( r Mit dem Pri t- enii ist folgendees möglich: * Ak i ierung bzw .e aktivierung dds A usdrucks (PRINT::O F FF oder O ).. ®° ufruf on A rufv H ilfe eimu sdruck( PRINTT H ELP?) ? . Ver wendudung d es Pr int-Menüs 1 D T ste S ve & Print b tätigetätigen, is PRINT: :(DRUCKEN)N) e scheint
looks at nine selected DSP address lines and three of the Data and Address bus control pins, (DPS), (DDS), and X/Y, and decodes them to produce chip enable control signals: (RAM_CE), (SID_CE), (STX_CE), (PHASE_CE), (ENCJIT_CE), and (COUNT_CE). DSP RAM address lines RA15 and RA16 are also decoded here.
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