Relative humidity computer

Claim 2

In a system for monitoring a condition of a given environment, a measuring apparatus comprising first sensing means for sensing a first parameter of the environment, second sensing means for sensing a second parameter of the environment, first amplifier means, input means for providing an input signal to said first amplifier means to enable said first amplifier means to provide an amplified output signal, said first and second sensing means being operable to control the gain of said first amplifier means whereby said output signal varies linearly with changes in the condition being monitored, said input means including second amplifier means for summing said output signal with a reference signal to provide said input signal for said first amplifier means.

Claim 3

A system as set forth in claim 1 wherein said first and second sensing means comprise first and second variable resistance devices having non-linear resistance characteristics, said first resistance device being connected to an input of said first amplifier means and said second resistance device being connected in a feedback path between an output of said first amplifier means and an input of said first amplifier means whereby the gain of said first amplifier means is determined by the ratio of the resistances of said second and first resistance devices.

Claim 4

A system as set forth in claim 1 wherein said first and second sensing means comprise first and second variable resistance devices, the resistances of said first and second resistance devices varying non-linearly with changes in said first and second parameters, respectively, and wherein said first amplifier means and said second amplifier means are connected in a positive feedback loop to linearize the gain of said first amplifier means.

Claim 5

In a system for measuring relative humidity within a given environment which is subject to variations in dewpoint and ambient temperatures, a measuring apparatus comprising first temperature sensing means for sensing the dewpoint temperature within said environment, second temperature sensing means for sensing the ambient temperature within said environment, first amplifier means, input means for providing an input signal to said first amplifier means, said first amplifier means being responsive to said input signal to provide an amplified output signal, said first and second temperature sensing means being operable to control the gain of said first amplifier means whereby said amplified output signal varies linearly with changes in the relative humidity of said environment, said input means including second amplifier means having an input and means for summing said output signal with a reference signal at said input to enable said second amplifier means to provide said input signal for said first amplifier means at an output of said second amplifier means which is connected to an input of said first amplifier means.

Claim 6

In a system for measuring relative humidity within a given environment which is subject to variations in dewpoint and ambient temperatures, a measuring apparatus comprising first temperature sensing means for sensing the dewpoint temperature within said environment, second temperature sensing means for sensing the ambient temperature within said environment, first amplifier means, input means for providing an input signal to said first amplifier means, said first amplifier means being responsive to said input signal to provide an amplified output signal, said first and second temperature sensing means being operable to control the gain of said first amplifier means whereby said amplified output signal varies linearly with changes in the relative humidity of said environment, said input means including second amplifier means having an input and means for summing said output signal with a reference signal at said input to enable said second amplifier means to provide said input signal for said first amplifier means at an output of said second amplifier means which is connected to an input of said first amplifier means.

Claim 7

A system as set forth in claim 4 wherein said first and second temperature sensing means comprise first and second thermistor means.

Claim 8

A system as set forth in claim 5 wherein said first thermistor means is connected to said input of said first amplifier means and said second thermistor means is connected in a feedback loop between an output of said first amplifier means and said input of said first amPlifier means whereby the gain of the first amplifier means is determined by the ratio of said second and first thermistor means.

Claim 9

A system as set forth in claim 6 wherein the resistances of said first and second thermistor means vary non-linearly with changes in said dewpoint and ambient temperatures, said first and second amplifier means being commected in a positive feedback loop to linearize the gain of said first amplifier means.

Claim 10

A system as set forth in claim 7 which includes first linearizing means connected between said input and said output of said first amplifier means, said first linearizing means being enabled whenever said input signal reaches a predetermined level to limit said input signal to thereby linearize the low end of the transfer characteristic for the measuring apparatus.

Claim 11

A system as set forth in claim 8 which includes second linearizing means connected between said input of said second amplifier means and said output of said second amplifier means, said second linearizing means being enabled whenever said output signal reaches a predetermined level to limit said output signal to thereby linearize the high end of the transfer characteristic for the measuring apparatus.

Claim 12

A system as set forth in claim 7 which includes means for adjusting the open loop gain of said positive feedback loop.

Claim 13

In a system for measuring relative humidity within a given environment which is subject to variations in dewpoint and ambient temperatures, a measuring apparatus comprising first and second amplifier means connected in a positive feedback loop with the output of said first amplifier means being connected to an input of said second amplifier means, and the output of said second amplifier means being connected to an input of said first amplifier means, said second amplifier means supplying an input signal to said first amplifier means, to enable said first amplifier means to provide an amplified signal at an output thereof which is extended to said input of said second amplifier means, and control means for controlling the gain of said first amplifier means in accordance with variations in the relative humidity of said environment to enable the output signal provided by said first amplifier means to vary linearly with changes in the relative humidity of said environment.

Claim 14

In a system for measuring relative humidity within a given environment which is subject to variations in dewpoint and ambient temperatures, a measuring apparatus comprising first and second amplifier means connected in a positive feedback loop with the output of said first amplifier means being connected to an input of said second amplifier means, and the output of said second amplifier means being connected to an input of said first amplifier means, said second amplifier means supplying an input signal to said first amplifier means, to enable said first amplifier means to provide an amplified signal at an output thereof which is extended to said input of said second amplifier means, and control means for controlling the gain of said first amplifier means in accordance with variations in the relative humidity of said environment to enable the output signal provided by said first amplifier means to vary linearly with changes in the relative humidity of said environment.

Claim 15

A system as set forth in claim 11 wherein said control means comprises first and second temperature sensing means for sensing ambient and dewpoint temperatures, respectively of said environment.

Claim 16

A system as set forth in claim 12 wherein said first and second temperature sensing means comprise first and second thermistors, respectively.

Claim 17

In a system for measuring relative humidity within a given environment which is subject to changes in ambient and dewpoint temperatures, a measuring apparatus comprising first and second resistive temperature sensing means for sensing the dewpoint and ambient temperatures, respectively of said environment, first and second amplifier means connected together in a positive feedback loop, first means connecting an output of said first amplifier means to an input of said second amplifier means, and second means, including said first temperature sensing means, connecting an output of said second amplifier means to an input of said first amplifier means, said second amplifier means providing an input signal for said first amplifier means to enable said first amplifier means to provide an amplified output signal at said output which is extended over said first means to said input of said second amplifier means, said second temperature sensing means being connected between said output and said input of said first amplifier means whereby the gain of said first amplifier means is determined by said second and first temperature sensing means, the resistances of said first and second temperature sensing means varying in accordance with variations in the dewpoint and ambient temperatures, respectively of said environment to causE a variation in the gain of said second amplifier means whereby the output signal provided by said second amplifier means varies linearly with changes in the relative humidity of said environment.

Claim 18

In a system for measuring relative humidity within a given environment which is subject to changes in ambient and dewpoint temperatures, a measuring apparatus comprising first and second resistive temperature sensing means for sensing the dewpoint and ambient temperatures, respectively of said environment, first and second amplifier means connected together in a positive feedback loop, first means connecting an output of said first amplifier means to an input of said second amplifier means, and second means, including said first temperature sensing means, connecting an output of said second amplifier means to an input of said first amplifier means, said second amplifier means providing an input signal for said first amplifier means to enable said first amplifier means to provide an amplified output signal at said output which is extended over said first means to said input of said second amplifier means, said second temperature sensing means being connected between said output and said input of said first amplifier means whereby the gain of said first amplifier means is determined by said second and first temperature sensing means, the resistances of said first and second temperature sensing means varying in accordance with variations in the dewpoint and ambient temperatures, respectively of said environment to causE a variation in the gain of said second amplifier means whereby the output signal provided by said second amplifier means varies linearly with changes in the relative humidity of said environment.

Claim 19

In a system for measuring relative humidity within a given environment which is subject to changes in ambient and dewpoint temperatures, a measuring apparatus comprising first and second resistive temperature sensing means for sensing the dewpoint and ambient temperatures, respectively of said environment, first and second amplifier means connected together in a positive feedback loop, said first amplifier means providing an input signal for said second amplifier means to enable said second amplifier means to provide an amplified output signal at an output thereof which is connected to an input of said first amplifier means, reference means for extending a reference signal to said input of said first amplifier means and means for adjusting said reference signal to establish an output range for said output signal, said first temperature sensing means being connected between an output of said first amplifier means and an input of said second amplifier means, and said second temperature sensing means being connected between said output and said input of said second amplifier means whereby the gain of said second amplifier means is determined by said second and first temperature sensing means, the resistances of said first and second temperature sensing means varying in accordance with variations in the dewpoint and ambient temperatures, respectively of said environment to cause a variation in the gain of said second amplifier means whereby the output signal provided by said second amplifier means varies linearly with changes in the relative humidity of said environment.

Claim 20

In a system for measuring relative humidity within a given environment which is subject to changes in ambient and dewpoint temperatures, a measuring apparatus comprising first and second resistive temperature sensing means for sensing the dewpoint and ambient temperatures, respectively of said environment, first and second amplifier means connected together in a positive feedback loop, said first amplifier means providing an input signal for said second amplifier means to enable said second amplifier means to provide an amplified output signal at an output thereof which is connected to an input of said first amplifier means, reference means for extending a reference signal to said input of said first amplifier means and means for adjusting said reference signal to establish an output range for said output signal, said first temperature sensing means being connected between an output of said first amplifier means and an input of said second amplifier means, and said second temperature sensing means being connected between said output and said input of said second amplifier means whereby the gain of said second amplifier means is determined by said second and first temperature sensing means, the resistances of said first and second temperature sensing means varying in accordance with variations in the dewpoint and ambient temperatures, respectively of said environment to cause a variation in the gain of said second amplifier means whereby the output signal provided by said second amplifier means varies linearly with changes in the relative humidity of said environment.

Claim 21

In a system for measuring relative humidity within a given environment which is subject to changes in ambient and dewpoint temperatures, a measuring apparatus comprising first and second resistive temperature sensing means for sensing the dewpoint and ambient temperatures, respectively of said environment, first and second amplifier means connected together in a positive feedback loop, said first amplifier means providing an input signal for said second amplifier means to enable said second amplifier means to provide an amplified output signal at an output thereof which is connected to an input of said first amplifier means, said first temperature sensing means being connected between an output of said first amplifier means and an input of said second amplifier means, and said second temperature sensing means being connected between said output and said input of said second amplifier means whereby the gain of said second amplifier means is determined by said second and first temperature sensing means, the resistances of said first and second temperature sensing means varying in accordance with variations in the dewpoint and ambient temperatures, respectively of said environment to cause a variation in the gain of said second amplifier means whereby the output signal provided by said second amplifier means varies linearly with changes in the relative humidity of said environment, and reference means for establishing a zero reference for said output signal.

Claim 22

In a system for measuring relative humidity within a given environment which is subject to changes in ambient and dewpoint temperatures, a measuring apparatus comprising first and second resistive temperature sensing means for sensing the dewpoint and ambient temperatures, respectively of said environment, first and second amplifier means connected together in a positive feedback loop, said first amplifier means providing an input signal for said second amplifier means to enable said second amplifier means to provide an amplified output signal at an output thereof which is connected to an input of said first amplifier means, said first temperature sensing means being connected between an output of said first amplifier means and an input of said second amplifier means, and said second temperature sensing means being connected between said output and said input of said second amplifier means whereby the gain of said second amplifier means is determined by said second and first temperature sensing means, the resistances of said first and second temperature sensing means varying in accordance with variations in the dewpoint and ambient temperatures, respectively of said environment to cause a variation in the gain of said second amplifier means whereby the output signal provided by said second amplifier means varies linearly with changes in the relative humidity of said environment, and reference means for establishing a zero reference for said output signal.