Abstract: A multiple capsule camera apparatus is disclosed to enhance the rate of detection and/or extend the overall imaging period. The multiple capsule camera apparatus coordinates the operations of the camera according to a schedule so that one camera may enter an active mode when the other camera is anticipated to have a low battery level. The capsule cameras may also coordinate their operations by communication with each other through a wireless link. A base station may also be used to coordinate the capsule camera operations with a wireless link established between the base station and each capsule camera.

Abstract: Apparatus and methods for removing dc offsets in feedback loops such as may be used in communication circuits are disclosed. A comparator may be used to sample the output of the feedback loop, with the comparator output applied to a DSP module. The DSP module is configured to determine a dc offset in the output signal and generate an offset correction signal, which may then be applied to the input of the feedback loop to adjust the de offset.

Abstract: Apparatus and methods for providing transmit signals in polar transmitters are described. A modulation signal may be provided from a VCO to low noise and low power signal paths and selectively combined based on a desired output power level. CMOS and CML divider circuits may be used to implement the low noise and low power signal paths respectively, and logic may be provided to select desired signals from the low noise and low power signal stages based on the desired output power level.

Abstract: Systems and methods of clock generation for radio frequency receiver. In radio frequency receiver, the system requires accurate local oscillating (LO) signal and system clocks for proper operation and to ensure high quality performance. In order to achieve accurate LO frequency and system clock, a crystal or and accurate reference clock is provide to the clock generation circuit. How a low-cost receiver, it is desirable to eliminate the requirement for a crystal or an accurate reference clock. The present invention discloses systems and methods to utilize a pilot signal embedded in the transmitted signal. The pilot signal usually has very accurate frequency which is particular true for broadcast system such as FM broadcast. In various embodiments of the present invention, the systems and methods measure the relation between the frequency of the pilot signal and the current clock generated.

Abstract: Systems of clock generation for integrated radio frequency receiver. In an integrated radio frequency receiver, a mixer is often used to down convert the incoming radio frequency signal. The down converted signal is then digitized and digital signal processing circuitry is used for efficient and flexible implementation of various functions to receive the underlying audio and/or data information. The mixer requires clock generation circuitry to provide a proper local oscillator signal for a selected channel. On the other hand, the digital signal processing circuitry requires its separate digital clock for proper operations. The clock generation system utilizes single local oscillator generation circuitry to provide the local oscillator signals required by the mixer and the digital clock signals required by the digital signal processing circuitry.

Abstract: An LNA circuit for providing a wide range of gain while maintaining the output headroom. In a radio frequency (RF) receiver, the signal received by the receiver may be extremely small. For a transmitter in a short distance, the received signal may be relatively strong. A low power amplifier usually is used to amplify the input signal. The LNA has to be designed to accommodate a wide range of gain. A convention LNA circuit supporting a wide range of gain often suffers from reduced output headroom due to increased current through the load resistor. The present invention discloses the use of current bleeding branch to allow a portion of current to flow through the current bleeding branch and consequently reduces the current that would have flown through the load resistor. Consequently, the voltage across the load resistor may be maintained low to allow adequate output headroom.

Abstract: FM radio transmitter is being widely used in portable devices as a convenient way to output audio contents to ubiquitously available FM radio receivers in cars or homes. However, the signal from the FM radio transmitter may be interfering with the signal being broadcast by an FM radio station. A scan system is incorporated into the FM radio transmitter to quickly and reliably identify a vacant channel for the FM radio transmitter to use. The scan system measures on-channel and out-of-channel signal quality and selects a best channel for transmission based on the measured on-channel and out-of-channel signal quality. The scan system is also incorporated into an FM radio receiver to quickly and reliably tune to a valid channel. The scan system selects the valid channel based on the measured on-channel and out-of-channel signal quality.

Abstract: A system and method of clock generation to provide divided-by-2 clocks with prescribed phase shifts are disclosed. In a communication system with high-order harmonic mixing, the system requires LO signals with a set of prescribed phase shifts, such as 0°, 45°, 90°, and 135°, or 0°, 60° and 120°. Often, the clock generation system involves a divide-by-2 divider to derive the clock signals with the prescribed phase shifts. In a conventional implementation of the divide-by-2 divider, the system is subject to phase uncertainty in the output signal. Accordingly, a system comprises multiple latch pairs and respective differential clocks are used to generate the clocks with the set of correct prescribed phase shifts.

Abstract: A system and method for sharing a switched capacitor array (SCA) by two tuning circuits are disclosed. In a multiple-band radio receiver, there is a need to use multiple tuning circuits for signals in different bands. The tuning circuit typically comprised an adjustable capacitance device and other tuning components, where the adjustable capacitance device is often implemented in SCA. The present invention discloses a system and method comprising n sections of capacitor elements where each capacitor element comprises a capacitor and switches to selectively connect the capacitor to one of the tuning circuit. Consequently, the SCA can be shared by the two tuning circuits. The control bits for the switched may be provided from a programmable control register.

Abstract: Systems and methods are provided for environment change sensing corresponding to the capsule camera entering the colon from the small intestine. In the environment change sensing mode, the capsule camera is operated in a very low power mode by configuring the image sensor to use a small region of interest or a high sub-sampling ratio. Image data is processed to estimate the light level. The variation of light level is used to detect environment change corresponding to entering the colon from the small intestine. Alternatively, the motion metric for a current frame and a reference frame is evaluated. The characteristic of the motion metric is extracted and used to detect environment change. In another configuration, the system determines environment change based on a combination of the variation of light intensity and the characteristic of the motion metric.

Abstract: A system and method for signal mixing using high-order harmonics of a local oscillation (LO) signal. In a radio frequency (RF) system, the input RF signal is converted to a lower frequency signal such as an intermediate frequency (IF) signal or a baseband signal for further processing. A voltage controlled oscillator (VCO) is often used to generate a VCO signal which is then divided down to provide the needed LO signals for down conversion. The present invention discloses a system and method for generating a composite harmonic signal based on a linear combination of divided down LO signals with specific phase shifts. Consequently a VCO signal with lower frequency can be used to conserve power. The composite harmonic signal is mixed with the input RF signal to generate a series of mixed signal including one associated with a high-order harmonic of the divided down LO signal.

Abstract: Apparatus and methods for improving the spectral performance of a polar modulator are described. A composite FM signal component of a composite polar transmit signal may be processed by monitoring the FM signal to detect a transient burst component, and, responsive to detection of a transient burst, generating a spectrally friendly replacement signal component that may be combined with the FM signal to improve spectral performance of the composite signal. In addition, an associated AM component of the composite transmit signal may be filtered to further improve spectral performance.

Abstract: Systems and methods for a capsule camera having on-board storage or wireless transmission to control image capture using motion information and to encode captured images based on motion compensated video compression are disclosed. In order to conserve the precious storage and power resources, the capsule camera measures motion metric to select a skip mode or a capture mode. In order to reduce computations related motion metric derivation, the motion metric is based on sub-images corresponding to a current frame and a previous captured frame instead of full-size images. When the skip mode is selected, the capsule camera exercises storage space/power conservation by skipping unnecessary image capture and/or reducing luminous energy of a light source or other means for power conservation. When the capture mode is selected, a full-size full-resolution frame is captured and compressed using motion-compensated video compression to achieve high compression ratio.

Abstract: Systems and methods are provided for displaying images captured from a capsule camera system. In order to increase the efficiency of viewing the image sequence, the image sequence is divided into multiple sub-sequences and the multiple sub-sequences are displayed in multiple viewing windows on a display screen concurrently. For images from a panoramic capsule system, the images typically have a very wide aspect ratio and may require different configuration for displaying in multiple viewing windows than that for image sequence having non-wide aspect ratio. The present invention also discloses methods and systems that divide a sequence from panoramic capsule camera into multiple member sequences and form an aggregated video. The aggregated video not only makes viewing more comfortable, but also speeds up viewing time.

Abstract: Systems and methods are provided for identifying dark areas in images captured by encapsulated cameras or endoscopes and enhancing the visibility of the dark area using intensity stretch. For capsule or endoscope images, there are often some dark areas caused by inadequate lighting. The poor visibility of detailed features in the dark area may reduce the detection rate of anomaly. The present invention calls for a method to detect the dark area based on contour. The intensities inside and outside the dark area are evaluated and are used to generate intensity transformation to stretch intensity in the dark area while minimizing the impact on the image quality outside the dark area.

Abstract: Apparatus and methods for adjustment of spectral signal characteristics in polar modulators are described. A composite signal detection circuit is configured to detect when a signal trajectory of a composite signal provided to the polar modulator passes near the origin of a complex plane associated with the composite signal, and then adjusts the composite signal to pass through the origin. A spectral adjustment circuit is described to adjust AM and FM or PM components of the composite signal to reduce the deviation of an FM component of the composite signal.

Abstract: Systems and methods for bandwidth reduction in polar modulation systems are described. Detection of problematic signal transition paths may performed, and then, dependent on the signal path, a correction signal may be generated and added to the signal to improve system performance. In typical implementations, detection of problematic signal paths may be performed by determining whether the signal transitions through a particular region in the signal constellation, such as a region about the origin, or whether the signal instantaneous frequency exceeds a predetermined threshold, and then responsively generating the correction signal.

Abstract: Apparatus and methods for enhancement of performance in polar modulators are described. In one implementation, an FM signal component is divided into a coarse FM signal and a residue FM signal to be applied to a VCO for generation of a modulation signal. The coarse FM signal may be proportional to a threshold value when the FM signal exceeds the threshold, while the residue FM signal may be proportional to the difference between the FM signal and coarse FM signal.

Abstract: A capsule camera apparatus includes a swallowable housing, a light source within the housing, a camera within the housing for capturing a first digital image and a second digital image of a view of the camera illuminated by the light source, a motion detector that detects a motion of the housing the first digital image and the second digital image, and a motion evaluator that selects a disposition of the second digital image, based on a metric on the motion. The disposition may include writing the second image into an archival storage or providing the second digital image to the outside by a wireless communication link.

Abstract: An alternate clock apparatus and method configured to reduce noise in selected frequency bands in an electronic device such as a communication device is described. In one embodiment the alternate clock includes a ring oscillator to generate multiple time shifted signals which may then be combined to generate clock signals at alternate frequencies to a primary reference. A resynchronization circuit may be coupled to the ring oscillator to periodically resynchronize the ring oscillator to a reference signal to reduce alternate clock jitter.