Page 8 - GB-4000 Brochure
P. 8

portant issue that leads the readers towards a          wave harmonics     at decreasing amplitudes.” Be-
        false conclusion.” Let us consider the square           low are two oscilloscope graphs of the GB-4000.

        wave waveform which was produced by the origi-              The one on the left shows a single square
        nal number 5 machine. It produces infinite har-         wave audio frequency running. The one on the
        monics and if we want “clarity of the signal” and       right shows 8 running simultaneously. Notice

        no “noise” we certainly would not want to use this      there is no loss of clarity or noise using the origi-
        waveform. But this would mean that these instru-        nal method developed in the 1930s/1950s. For

        ments would not work very well and no one               all of the documented information about the origi-
        would purchase them. Here is the definition of a        nal machines and running multiple frequencies
        square wave: “Square waves are equivalent to a          go to They have a Free 258

        sine  wave  at the same fundamental frequency           -page report that covers all of the machines.
        added to an  infinite  series of odd-multiple sine-     Chapters 5 through 12 cover this information.

           We have tried to stay true to the original ma-       Hertz to 3,800,000 Hertz. This gives much great-
        chine concepts while using modern technology.           er flexibility to the user so they have the option to
        The GB-4000 can run 1 single frequency at a             use various “carrier” frequencies. The Digital

        time or from 2 to 8 individual audio frequencies        Synthesizing Processor is capable of outputting 1
        simultaneously up to 40,000 Hertz. In order to          to 8 individual frequencies simultaneously up to

        output up to 8 individual audio frequencies simul-      40,000 Hertz. These frequencies are then
        taneously, we use 1 Digital Synthesizing Proces-        summed together so all of these frequencies are
        sor (or DSP) and 2 Direct Digital Synthesizers (or      at the same power level. They are then convert-

        DDS) for creating arbitrary waveforms from a sin-       ed to analog using a Digital-to-Analog Converter
        gle, fixed-frequency reference clock. The GB-           (DAC) and output from the GB-4000 into the

        4000 also uses a fixed crystal oscillator which is      M.O.P.A. or SR-4 15 watt amplifier. The 2 arbi-
        set at 3.1 MHz for our RF “carrier” frequency.          trary Direct Digital Synthesizers are used to out-
        The M.O.P.A. has its own variable “carrier” fre-        put up to 2 frequencies simultaneously from

        quency that covers a range from about 2,200,000         40,000 Hertz to 20 million Hertz.

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