Are 17 Frequencies Possible?

[Bud]

Do Minelab Detectors really penetrate the ground with 17 or more frequencies? Sure they are there, with the spread spectrum, but with what amplitude and power?? All frequencies have + and - harmonics right?? Hard to believe that they are able to peak all of those harmonics to be very useful. Just my thought on the subject, maybe I will be enlightened and proven wrong with the responses.

P.S. Besides, I think it would take a lot of power to push all those signals into the ground.
(even if they were able to tweak them up)

Thanks for any responses.

[Sean Goddard]

Re: Are 17 Frequencies Possible?

It is easy to produce well in excess of 17 frequencies, the REAL trick is to provide the "horsepower" to process them all.

I for one do not believe that the Sovereign has this power.

Having worked in Satcoms and Cellular, I have a good background to see the enormous amount of processing power to process just one frequency. OK, in these applications you are looking at things like Viterbi decoders and Fire encoders/decoders whereas in a beeper application there is nothing more than a simple phase analysis going on.

Look at your PC, do you have Winamp installed? That generates a complex waveform in realtime, BUT you probable have a 1GHz+ CPU, whereas the humble Sovereign only has a 4.6MHz CPU. A neat program called "Soundforge" will do a realtime FFT on an incoming signal, AND has to present this info in a graphical format on your monitor, and even a 1GHz Pentium 3 will struggle to give anything useful from this.

The Sovereign has a 8 bit ADC, your PC a 16 bit one. From Robert Hoolkos VERY perceptive article he concludes a bit resolution in excess of 12 bits is required. Again, the Sovereign might use range switching or process the signals in the analogue domain then simply use the ADC to determine a signal/no signal condition, as do most of the cheaper "digital" detectors.

The Tesoro Cortes only uses 8 bit, but it is sufficient to give a very good account of itself.

If you look at the patent, I believe the Sovereign actually uses the TIME domain, looking at the shifts in the pulses it sends out. So perhaps Mr. Candy was looking at the "bigger picture" when he claims a multifrequency capability. Rather than dealing with EACH frequency individually, he deals with the DIFFERENCES i.e. what's missing or added to the outgoing signal.