Apparatus for detecting the frequencies, intensities, and wave forms of magnetic and electromagnetic fields, comprising:
- a. a first magnetic field frequency, intensity and wave form receiving means;
- b. an input-output switching means;
- c. the first magnetic field frequency, intensity and wave form receiving means connected to said input-output switching means;
- d. an output switching means;
- e. a low pass circuit comprising low pass electronics and filtering means and first attenuator scale means;
- f. said first magnetic field frequency, intensity and wave form receiving means comprising a coil composed of a central coil winding wound around a non-conducting form containing a mumetal core therein, with the winding and core fully enclosed within a container made of conductive material which provides an electric field shield and including an opening to permit the leads from the winding to be connected to the input-output switching means with the leads being enclosed in a shield along the path from the container to the input-output switching means;
- g. said input-output switching means also connected to a power supply means;
- h. said input-output switching means also connected to said low pass electronics and filtering means;
- i. said low pass electronics and filtering means connected to said first attenuator scale means;
- j. said first attenuator scale means connected to a first variable resistor;
- k. said first variable resistor connector to said output switching means;
- l. said output switching means connected to a signal reading means;
- m. a second electromagnetic field frequency, intensity and wave form receiving means;
- n. said second electromagnetic field frequency, intensity and wave form receiving means comprising an antenna connected to said input-output switching means;
- o. a high pass circuit comprising high pass input equalizer network means, high pass electronics and filtering means, and second attenuator scale means;
- p. said input-output switching means also connected to both said high pass input equalizer network means, and said high pass electronics and filtering means;
- q. said high pass electronics and filtering means connected to said second attenuator scale means;
- r. said second attenuator scale means connected to a second variable resistor;
- s. said second variable resistor connected to said output switching network means;
- t. said input-output switching means further comprising means to route the signal received from said coil to either said low pass circuit or said high pass circuit, means to route the signal received from said antenna to said high pass circuit, and means to route the signal from the coil and the antenna simultaneously through the low pass circuit and high pass circuit respectively;
- u. first, second and third notch filter means for filtering out selected frequencies;
- v. said low pass electronics and filtering means further comprising:
- (i) a very low noise very high input impedance amplifier connected to said input-output switching means;
- (ii) said first notch filter means connected to said very low noise very high input impedance amplifier;
- (iii) said first notch filter means connected to a low frequency boost integrating amplifier circuit comprised of a Tee low pass network with a selected cutoff frequency, connected to an amplifier which amplifier is in turn connected to a power source and to an integrating feedback network composed of a resistor and capacitor in parallel with said amplifier which circuit serves to boost low frequencies which are in the range of 0.01 Hertz to 1 Hertz,
- (iv) the amplifier to said low frequency boost integrating amplifier circuit connected to said second notch filter means;
- (v) said second notch filter means connected to a current mirror transconductance amplifier circuit which serves to convert a voltage to a current and to further equalize the very low frequency components of the signal while at the same time reducing the voltage noise figure contributed by the other amplifiers;
- (vi) the amplifier of said current mirror transconductance amplifier circuit connected to a very high input impedance unity gain amplifier;
- (vii) said very high input impedance unity gain amplifier connected to said third notch filter means;
- p1 (viii) said third notch filter means connected to a power amplifier;
- w. said low pass electronics and filtering means connected to attenuator scale means which serves to select the intensity of the signal being received;
- x. a multiplicity of notch filter circuits connected in series for removing unwanted powerline fundamental frequency and harmonics;
- y. relay means to connect or disconnect said multiplicity of notch filter circuits to said high pass electronics and filtering means;
- z. said high pass electronics and filtering means further comprising:
- (i) an input amplifier for receiving the signal;
- (ii) said input amplifier connected to a gain setting network means which serves to select the intensity of the signal being received;
- (iii) the gain setting network means connected to an output amplifier in the high pass electronics and filtering means, which output amplifier can be adjusted to set the output gain of the output amplifier;
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- aa. said high pass input equalizer network comprising a balancing equalizing network connected to the input amplifier of said high pass electronics and filtering means, which is always operative at the same time as the input amplifier of the high pass electronics and filtering means, for linearizing the input from said coil or said antenna and making the correct matching impedance to mate with the input amplifier;
- bb. whereby when a frequency, intensity and wave form signal from a magnetic field is received by said coil or when a frequency, intensity and wave form signal from an electromagnetic field is received by said antenna, the signal is transmitted by the coil or antenna to said input-output switching means which is adjusted to allow the frequency, intensity and wave form from the magnetic field detected by the coil to travel through the low pass circuit or the high pass circuit or to allow the frequency, intensity and wave form from the electromagnetic field to travel through the high pass circuit, wherein the low pass circuit when receiving an input signal from the coil can detect magnetic frequencies in the range from approximately 0.1 Hertz to 500 Hertz and is sensitive down to 0.1 nano-Gauss and the high pass circuit when receiving an input signal from the coil can detect frequencies in the range from 0.1 Hertz to 50 Kilohertz and is sensitive down to 0.1 microgauss and the high pass circuit when receiving a signal from the antenna can detect electromagnetic frequencies in the range from approximately 1 kilohertz to 1 megahertz, and wherein said multiplicity of notch filters are actuated into the circuit when it is desired to measure frequencies below 300 Hertz in the high pass circuit.