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HiQSDR Direct Digital Conversion SDR Transceiver based on N2ADR-SDR. Pro/Contra Tayloe -SDR. PRO: Cheap and simple CONTRA: Witch switching ( Tayloe ) mixers , ( Softtrock , Pappradio usw) only the demodulation is „digital“, not the RF processing !
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HiQSDRDirect Digital Conversion SDR Transceiver based on N2ADR-SDR
Pro/Contra Tayloe-SDR PRO: Cheapand simple • CONTRA: Witchswitching (Tayloe) mixers, (Softtrock, Pappradio usw) onlythedemodulationis „digital“, not the RF processing! Due totheanalogueprocessingofthe I/Q-Signals, phantomsignalsand multiple receptionscanoccurwithinreceptionwindow The qualityofthe Soundcard is essential forthequalityofthewhole SDR-System No large distancesbetween Transceiver and PC, I/Q Signals aretransferredas analog Signals ! Low dynamicrange (<100dB), andweakIP3 is a resultofthe simple Mixing principle, Master oscillatorsignalishardtorejectfromAntenna, Deaf hole aroundzero Hertz IF due toinabilityof Soundcards todigitizelowfrequency / DC signals
Pro/Contra DirectConversion PRO: Complete digital processingfromantennetodemodulatedsignaloutput. Full digital I/Q processingresults in noamplitude / phaseerrors, nocorrectionsneeded Full digital processingevenforthe RF partresults in clean andexactsignalsandallowsthemaximumofpossiblelinearityoftheused ADC/DAC andtheirdynamicrange. Digital mixingwithcordicsproducesnomirrorsignals! Digital filteringwithcordincs / FIR Filters allows large usablebandwith (upto 1 - 2 MHz!) Hi resolutionof ADC/DAC allowshighusabledynamicrangeandresults in a good IP3 Digital processing in FPGA allowsnewfunctions / filters / functionsloaded „on-the-fly“ Transfer of digital data via Network allows large operatingrange & speed, only limited on therangeofthenetworkandallows easy remote operatedtransceivers. CONTRA: Higher cost due to FPGA und expensive ADC und DAC - converter
DDC = Direct Digital Conversion • Direct Digital Conversion= „Antenna to Bits“ principle • Full digital processing „directfromantenna“ withoutany analog conversionresults in best Signals andhighestFlexibility
FunctionprincipleHiQSDR: RX * Ultra-Low noisepreamplifiermatchesAntennato ADC. • 14-Bit, 125MHz AD-converterdigitizesthewholeSpectrumfrom60kHz – 66 MHz simultanous (!). * The data rate in FPGA is 1.7GBits/sec (!) • In theFPGA (Field Programmable Array) thesignalissampled, filtered (byCordicand FIR Filters) anddecimatedandconverted in digital 24-Bit wide I/Q signals • The Ethernet-Controller transfersthe I/Q-Samples to a PC. • The PC demodulatesthe I/Q-signalsandusethesoundcardonlyassoundoutputdevicetotheloudspeaker. • …only here the signal is again analogous …
FunctionprincpleHiQSDR: TX * Modulation signalgoes analog intotheinputof a Soundcard … fromhereitgoes digital * PC calculates I/Q-Samples, dependingoftheusedmodulation * Ethernet-Controller thansfersthe I/Q-Samples to FPGA in HiQSDR. * In FPGA (Field Programmable Array) the digital /IQ-Samples areinterpolatedand digital mixedtotheoutput RF signal * 14-Bit, 250MHz Digital-Analog-converterconvertesthe digital numbersto a sinusodialoutputsignal, the RF * A 7-pole Elliptic-Cauer- Low-Pass Filter at<70MHz supressHarmonicsandspurioussignalsandartifacts * MMIC booststhesignalto +17dBm (50mW)
The FPGA – Heart ofHiQTRX FPGA – Field Programmable Gate Array: Altera Cyclone-III –FPGA
FunctionprincpleHiQSDR: RF Input / Analog/Digital Conversion
FunctionprincipleHiQSDR: TX part / Digital-/Analog Conversion
Functionprincple HiQSDR: The Printed Circuit Board Heatspreader Fullassembled Board 4-Layer PCB
Functionprincple HiQSDR: theSoftware „QUISK“ Quiskcanbeusedunder Linux und Windows! Full 40m-Band on a contestday on onescreen…
HiQSDR: Measured Values: Residuals Residuals<90dB 7 MHz Residuals<90dB 45 MHz
HiQSDR: Measured Values: Phase Noise Phase Noise: <130dB/10kHz Screen: +/- 2.5kHz
HiQSDR: Future Modules underconstruction * Automatic PreselectorwithUltra-Low-Noise PreAmplifierfor all Amateur radiobands * 100-Watt Broadband Power AmplifierwithLowPass-Filter and optional ATU * Modern caseto fit all modulesfor a completetransceiver * Front-LCD toshow all workingparameters * Quiskwith zoom / variable filters * Latermaybe a DSP tohavenoneedfor a PC…..
HiQSDRDiscussion Groups / Infos @ WEB • Homepage von N2ADR: http://james.ahlstrom.name/transceiver/index.html • Homepage von DB1CC: http://www.db1cc.de/page2.html • Homepage von DL7LA: http://www.mydarc.de/dl7la/ • Deutsche Gruppe: http://www.mikrocontroller.net/topic/197747#2038410 • Yahoo-Group Deutsch: http://groups.yahoo.com/group/n2adr-sdr-deutsch/ • Yahoo-Group English: http://groups.yahoo.com/group/n2adr-sdr/