The current analog vs. digital scene is wrought with misconceptions and disinformation in the form of marketing hype. Such as, digitally generated frequencies do not vary, which implies that they do not have overtones and undertones. This would only be true if the frequencies remained digital. That is why digital frequencies from a DDS (Direct Digital Synthesis) and a DSP (Digital Signal Processing) are converted to analog before they are output from the GB-4000. These Digital-to-Analog Converters are called a DAC for short. You can see in the diagram above that a frequency comes out of a DDS or a DSP looking like stairs. The signal then goes through a DAC or Digital-to-Analog Converter. After this the frequency then goes through a Low-Pass or Bandpass Filter to finish the analog conversion. The final analog frequency is a very accurate analog frequency with all the overtones and undertones of an analog frequency. The analog frequency produced by a digital chip can be swept up or down with more accuracy than any old tube analog instrument. The most important thing to remember is the frequency has to be converted to analog before it is output from the frequency generator.

The GB-4000 uses 1 Digital Synthesizing Processor (DSP) and 2 Direct Digital Synthesizers (DDS) for creating arbitrary waveforms from a single, fixed-frequency reference clock. It also uses a fixed crystal oscillator which is set at 3.1 MHz for our RF carrier frequency. The 2 arbitrary waveform Direct Digital Synthesizers are used to output up to 2 frequencies simultaneously from 1 Hertz to 20 million Hertz. As for the 8 simultaneous frequency output, the Digital Synthesizing Processor is capable of outputting 2 to 8 individual frequencies simultaneously up to 40,000 Hertz. These frequencies are then summed together so all of the frequencies are at the same power level. They are then converted to analog using a Digital-to-Analog Converter (or DAC) and output from the GB-4000 and used with either the M.O.P.A. or the SR-4 15-watt amplifier.

Digitally produced frequencies converted to analog are far superior to any signal that comes from an old antique tube type analog frequency generator. Antique tube type generators are very limited. If we want a frequency of 1500.5, an old tube analog generator would not be accurate enough to give you that frequency to use. It could only give you 1500. Also, digitally converted frequencies allow you to sweep with far more accuracy than old analog tube type instruments. Even a thousandth or millionth of a frequency is possible even though this kind of accuracy is not needed. This is something that a purely analog instrument could not do as accurately. Digitally produced frequencies, when converted to analog, can accurately produce minute details. These analog frequencies when converted to a square wave waveform produce square wave harmonics. Some claim that their instruments, which output analog frequencies, produce advanced analog harmonics, but this is just sales hype. All the digital to analog frequency generators on the market today that we have tested with a spectrum analyzer produce the same analog harmonics. Any company claiming to have some form of superior advanced square wave harmonics are just giving the consumer lots of sales hype. So when it comes to Analog Vs. Digital frequencies make sure that the person you talk to knows the facts.