Telemetric measuring apparatus for biological objects
First Claim
1. Apparatus for measuring the value of a predetermined parameter in a biological object, comprising, in combination, transmitter means located outside of said object for transmitting a transmitter signal having a first frequency toward said biologicl object;
- first resonant circuit means located inside said object and having a resonant frequency varying from a first frequency as a function of said value of said parameter, for receiving said transmitter signal and modulating the same in correspondence to said value of said parameter, thereby furnishing a modulated transmitter signal;
second resonant circuit means connected to said first resonant circuit means and tuned to a second frequency different from said first frequency, for transmitting a resonant output signal in response to said modulated transmitter signal, the so-transmitted resonant output signal constituting a return signal;
signal receiver means located outside said object for receiving said resonant output signal and furnishing an indication thereof; and
output means connected to said transmitter means for changing the frequency of said transmitter signal until said resonant output signal has a maximum value indicative of correspondence between said transmitter signal frequency and said resonant frequency, the so-determined transmitter signal frequency constituting a measure of said value of said parameter.
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Accused Products
Abstract
Signals from a high frequency transmitter outside of the biological object are received in a resonant receiving circuit inside the object whose resonant frequency corresponds to the value of the parameter being measured. The signal from the resonant receiving circuit is applied to the input of a frequency multiplier whose output is connected to a second resonant circuit tuned to the multiplied frequency. The second resonant circuit transmits a return signal to a receiver outside of the biological object which is also tuned to the higher frequency. The signal at the receiver will have a maximum amplitude when the transmitter frequency is equal to the frequency of the first resonant circuit as tuned by the value of the parameter. The adjustment of the transmitter frequency required for receiving maximum energy at the receiver is a measure of the value of the parameter in a first embodiment. An alternate embodiment, the frequency of the transmitter is wobbled by means of a sawtooth voltage generator, the time difference between the sawtooth flyback and the maximum amplitude of the signal at the receiver constituting a measure of the value of the parameter.
33 Citations
14 Claims
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1. Apparatus for measuring the value of a predetermined parameter in a biological object, comprising, in combination, transmitter means located outside of said object for transmitting a transmitter signal having a first frequency toward said biologicl object;
- first resonant circuit means located inside said object and having a resonant frequency varying from a first frequency as a function of said value of said parameter, for receiving said transmitter signal and modulating the same in correspondence to said value of said parameter, thereby furnishing a modulated transmitter signal;
second resonant circuit means connected to said first resonant circuit means and tuned to a second frequency different from said first frequency, for transmitting a resonant output signal in response to said modulated transmitter signal, the so-transmitted resonant output signal constituting a return signal;
signal receiver means located outside said object for receiving said resonant output signal and furnishing an indication thereof; and
output means connected to said transmitter means for changing the frequency of said transmitter signal until said resonant output signal has a maximum value indicative of correspondence between said transmitter signal frequency and said resonant frequency, the so-determined transmitter signal frequency constituting a measure of said value of said parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- first resonant circuit means located inside said object and having a resonant frequency varying from a first frequency as a function of said value of said parameter, for receiving said transmitter signal and modulating the same in correspondence to said value of said parameter, thereby furnishing a modulated transmitter signal;
Specification