Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
169 words
A radio receiver comprising tuning circuit means for selecting a desired radiofrequency signal from the signals received by an antenna, local oscillator means having an output at a frequency substantially different from the frequency of said radiofrequency signal selected by said tuning circuit means, mixer circuit means for changing said radiofrequency signal into an intermediate frequency signal and which includes a balanced impedance bridge having a plurality of impedance arms and a field effect transistor having gate, source and drain electrodes and constituting one of said impedance arms between said gate and source electrodes, means for applying said selected radiofrequency from said tuning circuit means to said gate electrode, means for applying said output of the local oscillator means to said source electrode, and means operatively connecting said local oscillator means across said bridge so that the intermediate frequency signal appears at said drain electrode while leakage to the antenna of said local oscillator output is prevented and radiation of the local oscillator output by the antenna is avoided.
Claim 2
Dependent Claim
169 words
A radio receiver comprising tuning circuit means for selecting a desired radiofrequency signal from the signals received by an antenna, local oscillator means having an output at a frequency substantially different from the frequency of said radiofrequency signal selected by said tuning circuit means, mixer circuit means for changing said radiofrequency signal into an intermediate frequency signal and which includes a balanced impedance bridge having a plurality of impedance arms and a field effect transistor having gate, source and drain electrodes and constituting one of said impedance arms between said gate and source electrodes, means for applying said selected radiofrequency from said tuning circuit means to said gate electrode, means for applying said output of the local oscillator means to said source electrode, and means operatively connecting said local oscillator means across said bridge so that the intermediate frequency signal appears at said drain electrode while leakage to the antenna of said local oscillator output is prevented and radiation of the local oscillator output by the antenna is avoided.
Claim 3
Dependent Claim
140 words
A radio receiver in accordance with claim 1, wherein said plurality of impedance arms comprises a first impedance arm which is said one impedance arm having the gate and source electrodes respectively as end points, a second impedance arm having end points connected to the source electrode end point and to ground respectively, a third impedance arm having end points connected to the ground end point and a common end point of a fourth impedance arm, and said fourth impedance arm has its other end point connected to the gate electrode end point; said local oscillator is operatively connected across the bridge at the source electrode end point and said common end point, respectively, whereby leakage of the local oscillator output signal from the source electrode to the gate electrode across the impedance associated therewith to the antenna is prevented.
Claim 4
Dependent Claim
26 words
A radio receiver in accordance with claim 2, wherein the impedance of each of said arms is at least the capacitive reactance of the respective arm.
Claim 5
Dependent Claim
35 words
A radio receiver in accordance with claim 1, in which said tuning circuit means includes a plurality of tuned resonance circuits connected in series to achieve high selectivity in respect of the desired radiofrequency signal.