Frequency-programmed electron-capture detector

Claim 2

FOR USE IN COMBINATION WITH AN ELECTRON-CAPTURE DETECTOR AN IMPROVED PULSE-GENERATING CIRCUIT FOR PROVIDING AN OUTPUT SIGNAL HAVING A FREQUENCY CORRESPONDING TO AND EPRESENTATIVE OF THE CONCENTRATION OF AN ELECTRON-CAPTURING COMPOUND THE IMPROVED CIRCUIT COMPRISING: A. AMPLIFIER MEANS COUPLED TO THE ELECTRON-CAPTURE DETECTOR FOR PROVIDING AN OUTPUT SIGNAL REPRESENTATIVE OF THE RELATIVE CONCENTRATION OF AN ELECTRON -CAPTURING COMPOUND IN A SAMLE QUANTITY, B. PULSE GENERATOR MEANS COUPLED TO THE AMPLIFIER MEANS FOR PROVIDING PULSES OF VARIABLE FREQUENCIES WHICH FREQUENCIES VARY OVER A RANGE LESS THAN THE RANGES OF FREQUENCIES OF THE OUTPUT SIGNAL OF SAID CIRCUIT THE PULSE GENERATOR MEANS BEING OPERABLE IN RESPONSE TO THE AMPLIFIER MEANS OUTPUT SIGNAL, C. LIMIT DETECTOR MEANS COUPLED TO HE AMPLIFIER MEANS AND THE PULSE -GENERATOR FOR GENERATING A SIGNAL WHENEVER THE AMPLIFIER MEANS OUTPUT SIGNAL CONTROLLING THE PULSE-GENERATOR MEANS IS ABOVE OR BELOW THE OPERATING RANGE OF THE PULSE-GENERATOR MEANS AND D. FREQUENCY SELECTOR MEANS COUPLED TO HE PULSE-GENERATOR MEANS LIMIT DETECTOR MEANS AND THE ELECTRON-CAPTURE DETECTOR FOR REDUCING THE RANGE OF PULSE REPETITION FREQUENCIES FROM HE PULSE-GENERATOR MEANS THE FREQUENCY SELECTOR MEANS BEING OPERABLE IN RESPONSE TO THE OUTPUT SIGNAL OF THE LIMIT DETECTOR MEANS, WHEREBY THE RATE OF PULSES APPLIED TO THE ELECTRON-CAPTURE DETECTOR WILL MAINTAIN THE AMPLIFIER MEANS OUTPUT SIGNAL WITHIN THE OPERATING RANGE OF THE PULSE-GENERATOR MEANS SO THAT A SIGNAL HAVING A FREQUENCY PROPORTIONAL TO AND REPESENTATIVE OF THE CONCENTRATION OF AN ELECTRON-CAPTURING COMPOUND IN A SAMPLE IS FED BACK FROM THE PULSE-GENERATOR MEANS TO THE ELECTRON CAPTURE DECTOR.

Claim 3

The circuit of claim 1, above, wherein said pulse-generator means comprises a voltage-controlled oscillator operable over a frequency range on the order of 2 to 1.

Claim 4

The circuit of claim 1, above, wherein the limit detector means comprises: a. amplitude-discriminator means coupled to the amplifier means output signal controlling the pulse-generator means for determining the magnitude of the amplifier means output voltage; b. delay means coupled to the amplifier-discriminator means for permitting one step of the selector to take place before additional steps occur; and c. counter means coupled to the delay means and the amplifier means for generating a signal whenever the signal controlling the pulse-generator means is above or below its normal operating range.

Claim 5

The circuit of claim 1, above, wherein the frequency selector means comprising: a. a plurality of binary-counting means coupled to the pulse generator means for providing the function of a 10-bit binary frequency divider that produces selectable output frequencies of Fo/2, Fo/4, Fo/8, et cetera down to Fo/1024; and b. signal selector means coupled to the binary-counting means for selecting an output frequency from the binary-counting means.

Claim 6

The circuit of claim 1, above, further comprising: frequency-to-voltage-converting means coupled to the frequency selector means for providing an output voltage signal proportional to and representative of the frequency of the pulsed signal applied to the electron-capture detector.

Claim 7

The circuit of claim 1, above, fuRther comprising: audible output means coupled to the frequency selector means for generating an audible output tone whose pitch corresponds to and is representative of the frequency of the pulsed signal applied to the electron-capture detector.

Claim 8

The circuit of claim 1, above, further comprising: audible output means coupled to a frequency-to-voltage-converting means for generating an audible output tone whose pitch corresponds to and is representative of the frequency of the pulsed signal applied to the electron-capture detector.

Claim 9

The circuit of claim 1, above, wherein the pulsed signal applied to the electron-capture detector has a pulse repetition frequency of 5 Mhz response to high concentration of an electron-absorbing compound and a pulse repetition of 5 kHz in response to an absence of electron-capturing compound in a sample quantity.

Claim 10

The circuit of claim 1, above, further comprising digital output means coupled to the frequency selector means for further dividing its output frequency to a range compatible with digital output devices, whereby the digital output corresponds to and is representative of the concentration of electron-capturing compound in a sample quantity.

Claim 11

The circuit of claim 4, above, further comprising: pulse shaping means coupled to the signal selector means for producing pulses of width and amplitude which will operate the electron-capture detector.

Claim 12

For use in combination with an electron-capture detector, an improved pulse-generating circuit for providing an output signal having a frequency corresponding to and representative of the concentation of an electron-capturing compound, the improved circuit comprising: a. amplifier means coupled to the electron-capture detector for providing an output signal representative of the relative concentation of an electron-capturing compound in a sample quantiy; b. a voltage-controlled oscillator, operable over a frequency range of approximately 2 to 1, coupled to the amplifier means for providing pulses of variable frequencies which frequencies vary over a range less than the range of frequencies of the output signal of said circuit, the voltage-controlled oscillator being operable in response to the amplifier means output signal; c. amplitude-discriminator means coupled to the amplifier means output signal controlling the voltage-controlled oscillator for determining the magnitude of the amplifier means output voltage; d. delay means connected to the amplifier-discriminator means for permitting one step of the selector to take place before additional steps occur; e. counter means connected to the delay means and the amplifier means for generating a signal whenever the signal controlling the voltage-controlled oscillator means is above or below its operating range; and f. frequency selector means coupled to the voltage-controlled oscillator, and amplifier-discriminator means, the delay means, the counter means, and the electron-capture detector, the frequency selector means being operable in response to the output signal of the counter means.

Claim 13

For use in combination with an electron-capture detector, an improved pulse-generating circuit for providing an output signal having a frequency corresponding to and representative of the concentation of an electron-capturing compound, the improved circuit comprising: a. amplifier means coupled to the electron-capture detector for providing an output signal representative of the relative concentation of an electron-capturing compound in a sample quantiy; b. a voltage-controlled oscillator, operable over a frequency range of approximately 2 to 1, coupled to the amplifier means for providing pulses of variable frequencies which frequencies vary over a range less than the range of frequencies of the output signal of said circuit, the voltage-controlled oscillator being operable in response to the amplifier means output signal; c. amplitude-discriminator means coupled to the amplifier means output signal controlling the voltage-controlled oscillator for determining the magnitude of the amplifier means output voltage; d. delay means connected to the amplifier-discriminator means for permitting one step of the selector to take place before additional steps occur; e. counter means connected to the delay means and the amplifier means for generating a signal whenever the signal controlling the voltage-controlled oscillator means is above or below its operating range; and f. frequency selector means coupled to the voltage-controlled oscillator, and amplifier-discriminator means, the delay means, the counter means, and the electron-capture detector, the frequency selector means being operable in response to the output signal of the counter means.

Claim 14

The circuit of claim 11, above, where the frequency selector means comprising: a. a plurality of binary-counting means connected to the voltage-controled oscillator for providing the function of a 10-bit binary frequency divider that produces selectable output frequencies of Fo/2, Fo/4, Fo/8, et., down to Fo/1024; and b. signal selector means connected to the binary-counting means for selecting the output frequency from the binary counting means.

Claim 15

For use in combination with an electron-capture detector, an improved pulse-generating circuit for providing an output signal having a frequency corresponding to and representative of the concentration of an electron-capturing compound, an improved circuit comprising: a. amplifier means coupled to the electron-capture detector for proViding an output signal representative of the relative concentration of an electron-capturing compound in a sample quantity; b. a voltage-controlled oscillator, operable over a frequency range of approximately 2 to 1, coupled to the amplifier means for providing pulses of variable frequencies which frequencies vary over a range less than the range of frequencies of the output signal of said circuit, the voltage-controlled oscillator being operable in response to the amplifier means output signal; c. amplitude-discriminator means coupled to the amplifier means output signal controlling the voltage-controlled oscillator for determining the magnitude of the amplifier means outut voltage; d. delay means connected to the amplifier-discriminator means for permitting one step of the selector to take place before additional steps occur; e. counter means connected to the delay means and the amplifier means for generating a signal whenever the signal controlling the voltage-controlled oscillator means is above or below its operating range; f. a plurality of binary-counting means connected to the voltage-controlled oscillator for providing the function of a 10-bit binary frequency divider that produces selectable output frequencies of Fo/2, Fo/4, Fo/8, etc., down to Fo/1024; and g. signal selector means connected to the binary-counting means for selecting the output frequency from the binary counting means. h. frequency-to-voltage-converting means coupled to the signal selector means for selector means for providing an output voltage signal proportional to and representative of the frequency of the pulsed signal applied to the electron-capture detector; i. audible output means coupled to the signal selector means for generating an audible output tone whose pitch corresponds to and is representative of the frequency of the pulsed signal applied to the electron-capture detector; j. digital output means coupled to the signal selector means for further dividing its output frequency to a range compatible with digital output devices, whereby the digital output corresponds to and is representative of the concentration of electron-capturing compound in a sample quantity; and k. pulse shaping means coupled to the signal selector means for producing pulses of widths and amplitudes which will operate the electron-capture detector.

Claim 16

For use in combination with an electron-capture detector, an improved pulse-generating circuit for providing an output signal having a frequency corresponding to and representative of the concentration of an electron-capturing compound, an improved circuit comprising: a. amplifier means coupled to the electron-capture detector for proViding an output signal representative of the relative concentration of an electron-capturing compound in a sample quantity; b. a voltage-controlled oscillator, operable over a frequency range of approximately 2 to 1, coupled to the amplifier means for providing pulses of variable frequencies which frequencies vary over a range less than the range of frequencies of the output signal of said circuit, the voltage-controlled oscillator being operable in response to the amplifier means output signal; c. amplitude-discriminator means coupled to the amplifier means output signal controlling the voltage-controlled oscillator for determining the magnitude of the amplifier means outut voltage; d. delay means connected to the amplifier-discriminator means for permitting one step of the selector to take place before additional steps occur; e. counter means connected to the delay means and the amplifier means for generating a signal whenever the signal controlling the voltage-controlled oscillator means is above or below its operating range; f. a plurality of binary-counting means connected to the voltage-controlled oscillator for providing the function of a 10-bit binary frequency divider that produces selectable output frequencies of Fo/2, Fo/4, Fo/8, etc., down to Fo/1024; and g. signal selector means connected to the binary-counting means for selecting the output frequency from the binary counting means. h. frequency-to-voltage-converting means coupled to the signal selector means for selector means for providing an output voltage signal proportional to and representative of the frequency of the pulsed signal applied to the electron-capture detector; i. audible output means coupled to the signal selector means for generating an audible output tone whose pitch corresponds to and is representative of the frequency of the pulsed signal applied to the electron-capture detector; j. digital output means coupled to the signal selector means for further dividing its output frequency to a range compatible with digital output devices, whereby the digital output corresponds to and is representative of the concentration of electron-capturing compound in a sample quantity; and k. pulse shaping means coupled to the signal selector means for producing pulses of widths and amplitudes which will operate the electron-capture detector.