The development of electronic measuring equipment, and especially, with built-in microprocessors, now lets take another look at the detectors, whose operation is based on measuring the frequency drift measurement oscillatory circuit.
Modern techniques make it possible to implement compact device that allows in real time to estimate with high accuracy small deviation frequency of the measuring oscillator. And although built on this principle the electronic detector is undoubted relative device "on the beat", he deserves highlighting in a separate class devices that can be called metal detectors on the principle of electronic the frequency counter. Devices of this class, along with tons of service capabilities microprocessor implementation, have another significant difference from the simplest devices "on the beat" - the ability to assess the sign of the frequency increment.
Given that the ferromagnetic target usually leads to a decrease in frequency "measurement of the generator, and a target made of metal-neuromagnetic - up, get the wonderful opportunity of selection of targets by type of metal. In addition, this class of devices is practically not affected by the effect described above spurious synchronization, since the frequency of the measuring oscillator and frequency other auxiliary signals (clock frequency of the microprocessor) is very differ. This allows to increase the sensitivity.
The positive side for practice is the simple design of the sensor and electronic detectors on the beats and on the principle of frequency. Like this the device can be very compact. It is convenient to use when something already discovered a more sensitive device. If the detected object is small and is deep enough in the ground, he can "get lost", to move in during the excavation.
So many times do not "browse" bulky sensitive the metal detector of the site, preferably at the final stage to control their move is a compact instrument with a very small radius of action, which can more accurately to learn the location of the subject.
Author: A. I. Shchedrin