Patent
Tunable notch filter for image frequency and conducted local oscillator leakage rejection
TLDR
In this article, a tunable notch filter for the front end of an RF receiver includes magnetically coupled input and output tunable stages each responsive to a tuning voltage provided by the receiver.Abstract:
A tunable notch filter for the front end of an RF receiver includes magnetically coupled input and output tunable stages each responsive to a tuning voltage provided thereto. Each of the input and output stages includes a respective series and parallel resonant circuit wherein the parallel resonant circuits are tuned to a selected RF frequency and the series resonant circuits are tuned to a frequency approximately equal to that of a local oscillator. By using the series resonant circuits to create a notch at a frequency approximating that of the local oscillator, conducted local oscillator leakage from the receiver's antenna is substantially reduced and local oscillator image frequency rejection is substantially improved.read more
Citations
More filters
Patent
Wireless energy repeater
TL;DR: In this paper, the authors presented a self-resonant circuit tuned to resonate at substantially the same resonant frequency as a resonant transmitting coil in a wireless charger, the resonant receiving coil operating as a magnetically coupled resonator with the transmitting coil.
Patent
Safety feature for wireless charger
TL;DR: In this paper, a power control circuit is coupled between the power source and the transmitting coil, having a control input configured to control power delivered from the source to the transmitting coils as long as the user is closer than a threshold distance.
Patent
Active image separation mixer
TL;DR: In this paper, a mixer separates IF components IF1, IF2 of the same frequency which are images of different frequency RF signals RF1, RF2 beating with a given LO signal is applied to a FET active power divider and applied to the drains of a pair of balanced FET mixing elements.
Patent
Planar active endfire radiating elements and coplanar waveguide filters with wide electronic tuning bandwidth
TL;DR: In this paper, a planar microwave and millimeter-wave system component is fabricated by using slotlines extending from the periphery of a CPW resonator, allowing the degree of electrical coupling between the CPW and and the slotlines to be adjusted for matching.
Patent
RF notch filter having multiple notch and variable notch frequency characteristics
TL;DR: In this article, a filter network having the capability of establishing multiple, tunable notch frequencies is described. But the authors focus on the downlink of the network, where a notch filter path is established for each notch frequency and includes a bandpass filter and inverter.
References
More filters
Patent
Pre-tuner tracking traps responsive to a tuning voltage
TL;DR: In this paper, two tunable traps are incorporated between the RF input and the tuner to attenuate undesired signals symmetrically located in frequency below and above respective desired RF carriers.
Patent
Electrical filter arrangement
TL;DR: In this paper, a highly selective electrical filter network composed of passive circuit elements and capable of attenuating or notching only selected frequencies from a band while freely passing without substantial attenuation the remaining frequencies in the band is described.
Patent
UHF-VHF tuner having damping means to reduce interference in UHF band
Ijichi Sadayoshi,Eiji Nishizawa +1 more
TL;DR: In this paper, an electronic tuner capable of selectively receiving the UHF band and high and low channels in the VHF band is described which has a suitable resistance provided across power supply terminals in order to improve the separation between VHF mode and UHF mode.
Patent
Tracking image frequency trap
TL;DR: In this paper, the circuit impedance is selected to cause cancellation in the inductive branch between image frequency component coupled by the first coupling and image frequency components coupled by a second coupling, without substantially affecting the desired signals.