A handheld electronic device may be provided that contains a conductive housing and other conductive elements. The conductive elements may form an antenna ground plane. One or more antennas for the handheld electronic device may be formed from the ground plane and one or more associated antenna resonating elements. Transceiver circuitry may be connected to the resonating elements by transmission lines such as coaxial cables. Ferrules may be crimped to the coaxial cables. A bracket with extending members may be crimped over the ferrules to ground the coaxial cables to the housing and other conductive elements in the ground plane. The ground plane may contain an antenna slot. A dock connector and flex circuit may overlap the slot in a way that does not affect the resonant frequency of the slot. Electrical components may be isolated from the antenna using isolation elements such as inductors and resistors.

Wireless Handheld Electronic Device

An inventory management system which includes a transponder, an interrogation transceiver and control devices utilized therewith. The control devices operate to minimize the power consumption of the transponder while permitting selected, coded operation of the inventory management system. The interrogation transceiver provides linkage to the transponder by means of a modulated radio frequency (RF) carrier during system operation. A transmit/receive switch is also included in the invention to prevent harmful coupling between the transponder receiver and the transponder transmitter. This could occur during data exchanges between the transponder and the interrogation receiver.

Inventory management system

A resonance exciting coil (C) excites magnetic resonance in nuclei disposed in an image region in which a main magnetic field and transverse gradients have been produced. A flexible receiving coil (D) includes a flexible plastic sheet (40) on which one or more loops (20) are adhered to receive signals from the resonating nuclei. Velcro straps (46) strap the flexible sheet and the attached coil into close conformity with the surface of the portion of the patient to be imaged. An impedance matching or coil resonant frequency adjusting network (50) is mounted on the flexible sheet for selectively adjusting at least one of an impedance match and the peak sensitivity resonant frequency of the receiving coil. A preamplifier (52) amplifies the received signals prior to transmission on a cable (24). A selectively variable voltage source (70) applies a selectively adjustable DC bias voltage to the cable for selectively adjusting at least one of the impedance match and the LC resonant frequency of the receiving coil. The received signals are amplified by an amplifier (82) and processed by an image processor (30) to form man-readable images of the examined region of the patient for display on a video display (32) or the like.

Surface coil system for magnetic resonance imaging

A television tuning system includes a memory for storing tuning information with first and second groups of memory locations for storing different tuning information for the same group of predetermined channels. A mode switch, in a first mode, allows memory locations in the first group to be addressed when channels in the predetermined group are selected and in a second mode allows memory locations in the second group to be addressed when channels in the predetermined group are selected. Such an arrangement is useful in a motel, hotel or hospital to allow certain channels in a list of channels to be selected when a rental fee has been paid and to exclude those certain channels when the rental fee has not been paid.

Tuning mode arrangement useful for restricting channel selection to certain channels

An electronic device has wireless communications circuitry including an adjustable antenna system coupled to a radio-frequency transceiver. The adjustable antenna system may include one or more adjustable electrical components that are controlled by storage and processing circuitry in the electronic device. The adjustable electrical components may include switches and components that can be adjusted between numerous different states. The adjustable electrical components may be coupled between antenna system components such as transmission line elements, matching network elements, antenna elements and antenna feeds. By adjusting the adjustable electrical components, the storage and processing circuitry can tune the adjustable antenna system to ensure that the adjustable antenna system covers communications bands of interest.

Tunable antenna systems

RCA 70,849 TELEVISION TUNING SYSTEM WITH PROVISIONS FOR RECEIVING RF CARRIER AT NONSTANDARD FREQUENCY Abstract of Disclosure A tuning system for a television receiver includes a phase locked loop for tuning a local oscillator to the nominal local oscillator frequencies required to tune the receiver to RF carriers at standard broadcast frequencies allocated to the various channels a viewer may select. The tuning system also includes an automatic fine tuning (AFT) frequency discriminator fox tuning the local oscillator to minimize any deviation between the frequency of an actual picture carrier and the nominal picture carrier frequency. If the receiver is coupled to a television distribution system which provides RF carriers having nonstandard freq-uencies arbitrarily near respective ones of the standard broadcast frequencies, when the phase locked loop has achi-eved lock at a nominal frequency, a mode control unit selectively couples the discriminator and a frequency drift control circuit to the local oscillator. If the frequency of the local oscillator drifts more than a predetermined off-set from the frequency synthesized under phase locked loop control because no carrier has been detected by the discrim-inator, discriminator and drift control are terminated so that the receiver will not be tuned to an undesired carrier such as, for example, the lower adjacent channel sound carr-ier, and phase locked loop control is reinitiated to synthe-size a local oscillator signal having a frequency incremented from the frequency of the originally synthesized local oscillator signal by a predetermined amount. After the phase locked loop is locked at an incremented frequency, discriminator control is again initiated. If, during this cycle of discriminator control, the local oscillator again drifts more than the predetermined offset from the RCA 70,849 incremented local oscillator frequency because no carrier is detected by the discriminator, phase locked loop control is again reinitiated to synthesize a local oscillator signal having a frequency decremented from the frequency of the originally synthesized local oscillator signal by the pre-determined amount. If during any discriminator control cycle the local oscillator has not drifted further than the predetermined offset because the discriminator has tuned the local oscillator to a carrier within the predetermined offset, phase locked loop control is not reinitiated and the tuning sequence is complete. -1a-

Television tuning system with provisions for receiving rf carrier at nonstandard frequency

Tuning circuitry for a VHF television (TV) antenna tunes such antenna for signals corresponding to the TV channel selected and couples those signals to the tuning system of a television receiver. An antenna has a pair of signal terminals across which the tuning circuitry connects to form a resonance circuit therewith for tuning the antenna. A variable capacitance responds to a control voltage to develop the appropriate value of tuning capacitance. Impedances, e.g. inductors or capacitors or resistors, are coupled to the resonance circuit at least at selected times by switches. An amplifier couples signals from the resonance circuit to the tuning system of the TV receiver.

Automatic tuning circuit arrangement with switched impedances

A single-turn loop antenna suitable for inclusion within the cabinet of a television receiver has at least one gap forming a pair of feed terminals. Circuitry connects to the feed terminals for tuning the antenna over at least a portion of the television frequency bands and for coupling signals from the feed terminals to a transmission line. The circuitry provides isolation so the tuning of the antenna by the tuning circuitry is unaffected by the impedance of the transmission line or its terminating impedance and variations thereof. The circuitry is affixed to the loop proximate to the feed terminals, and the transmission line is affixed to the periphery of the loop and departs therefrom at a neutral point located, for example, opposite to the gap.

Loop antenna arrangements for inclusion in a television receiver

In a phase locked loop (PLL) tuning system for a television receiver, the capability of tuning channels with RF signals with non-standard frequencies arbitrarily near the respective standard frequencies is provided by making a frequency divider used in the PLL for establishing the frequency relationship of the local oscillator signal to the crystal oscillator signal controllable in a limited range corresponding to a frequency range less than the frequency separation between channels. As one feature of this system the divider is controlled in accordance with predetermined AFT signal conditions. As another feature, the division factor of the divider is initially offset from its nominal value corresponding to the standard frequency for the selected channel and thereafter the frequency of the local oscillator signal is controlled in response to the AFT signal.

Television frequency synthesizer for nonstandard frequency carriers

In a sweep type tuning system capable of sweeping through a desired range of carrier frequencies selectively in one of two directions, a carrier detector includes a discriminator for generating a discriminator signal as the frequency range is swept which has a first amplitude portion when the frequency of a tuned carrier is less than a predetermined nominal value and a second amplitude portion when the frequency of the tuned carrier is greater than the predetermined nominal value. A sequence detector determines the sequence of generation of the first and second portions of the discriminator signal to generate a signal indicating the presence of the tuned carrier. The presence indicating signal is generated when the sweeping takes place in a first direction if the first and then the second portions are sequentially generated and when the sweeping takes place in the second direction if the second and then first portion are sequentially generated.

John G. N. Henderson

Papers

Television tuning system with provisions for receiving rf carrier at nonstandard frequency

Automatic tuning circuit arrangement with switched impedances

Loop antenna arrangements for inclusion in a television receiver

Television frequency synthesizer for nonstandard frequency carriers

Carrier detector apparatus useful in a multiband sweep type tuning system