Abstract: A PLL-based frequency synthesizer is provided. In accordance with one aspect, a phase locked loop is provided that comprises a phase detector, a loop filter, a voltage controlled oscillator, and a feedback circuit. The phase detector has as inputs a reference frequency signal and a feedback signal. The phase detector is operable to generate a phase detection signal based on a comparison of phases between the reference frequency signal and the feedback signal. The loop filter is coupled to the phase detector for receiving the phase detection signal and generates an output voltage in response to the phase detection signal. The voltage controlled oscillator is coupled to the output voltage of the loop filter and generates a local oscillator signal. The feedback circuit is coupled to the local oscillator signal and generates the feedback signal. The feedback circuit comprises a sampling circuit.

Abstract: A hand-held electronic device with a keyboard optimized for use with the thumbs is disclosed. In order to operate within the limited space available on a hand-held electronic device, the present invention optimizes the placement and shape of the keys, preferably using keys that are oval or oblong in shape, and that are placed at angles designed to facilitate thumb-typing. The angles at which keys on either side of the keyboard are placed is complimentary.

Abstract: An impedance matching low noise amplifier (“LNA”) having a bypass switch includes an amplification circuit, a bypass switching network and a match adjustment circuit. The amplification circuit has an amplifier input and an amplifier output, and is configured to receive a radio frequency (RF) input signal at the amplifier input and apply a gain to generate an amplified RF output signal at the amplifier output. The bypass switching network is coupled to a low-gain control signal and is also coupled between the amplifier input and the amplifier output. The bypass switching network is configured to couple the amplifier input to the amplifier output when the low-gain control signal is enabled in order to feed the RF input signal through to the RF output signal. The match adjustment circuit is coupled to the low-gain control signal and the RF input signal, and is configured to couple the RF input signal to an impedance when the low-gain control signal is enabled.

Abstract: A portable battery charger for a mobile device having a rechargeable battery includes battery contacts, a switching regulator, and a charger interface. The battery contacts are configured to receive a battery having a low-voltage value. The switching regulator is coupled to the battery contacts and configured to draw the low-voltage value from the battery and convert the low-voltage value to a charger output. The charger interface is configured to electrically engage the mobile device and is further configured to couple the charger output from the switching regulator to the rechargeable battery in the mobile device.

Abstract: An integrated circuit packaging assembly for reducing the length of bond wires transmitting radio frequency signals is disclosed herein. The die is offset in the packaging to position a subset of its bond pads in close proximity to package bond pads to allow for shorter bond wires, which reduces the inductive reactance that is induced in longer wires by high frequency signals. The subset of the bond pads is used for RF transmissions, while the other bond pads are used for direct current and low frequency signals.

Abstract: A clock signal duty cycle control circuit is provided that receives an incoming signal from a clock signal input source and generates an improved output clock signal having an accurately controlled duty cycle. The circuit controls the duty cycle of the output clock signal by comparing the incoming signal to a reference value in a comparator. The reference value is derived from a reference charge stored on a capacitor. The reference charge is built up in the capacitor using the currents from a current source and a current sink, which are controlled using translated output signals from the comparator.

Abstract: An adaptive tuning method for a wireless communication device determines the impedance of a matching circuit relative to an impedance to be matched and adjusts the impedance of the matching circuit accordingly. A passive surface acoustic wave (SAW) device includes multiple terminated interdigital transducers (IDTs) which generate reflected SAWs when excited by incident SAWs, each reflected SAW having magnitude and phase characteristics dependent upon the particular IDT termination. According to the invention, the IDT terminations include the impedance matching circuit and the impedance to be matched. Input IDTs in the SAW device are excited with electrical signals, which are converted to generate the incident SAWs. The resultant reflected SAWs are converted by output IDTs into output electrical signal signals which can then be analyzed to determine magnitude and phase differences between the output electrical signal signals and generate an impedance matching circuit control signal based thereon.

Abstract: A portable electronic device includes a log-structured file system implemented in flash memory, The log-structured file system includes a write function for storing contiguous data records to the flash memory in the form of at least one data log, although the system may write data records to the flash memory using a plurality of data logs. The log-structured file system also includes a read function for retrieving data records from the one or more logs using a plurality of memory mapped pointers, which may be stored in an associated RAM index, or which may be implemented as an index stored in the flash memory. A clean-log function is also provided for eliminating inactive records from the log so that new data can be appended to the end of the log. The various functions associated with the log-structured file system are implemented as at least three software modules, a read module, a write module and a clean-log module, although other configurations are possible.

Abstract: A hand-held electronic device with a keyboard, thumbwheel, display and associated software is optimized for use of the device with the thumbs. The associated software has a plurality of features to optimize efficient use of the limited keyboard space and encourage the use of the device by thumb-based data entry through the thumbwheel and/or through a combination of minimal number of keystrokes. Software features include international character scrolling, and auto-capitalization. The keys on the device keyboard are optimally shaped and configured for thumb-based input. In addition, the thumbwheel is inclined between the front and a side edge of the device so as to be reachable by either the thumb or index finger of the user's hand at the side edge of the device.

Abstract: A direct digital frequency synthesizer and a hybrid frequency synthesizer combining the direct digital frequency synthesizer and a phase locked loop is provided. The direct digital frequency synthesizer includes a phase accumulator that is configured to generate a discrete phase signal. Spurious phase modulation in the discrete phase signal is reduced by a noise shaper, and the output of the noise shaper is then used to address a phase-to-amplitude translator. The phase-to-amplitude translator generates a discrete waveform which is converted to a continuous waveform by a digital to analog converter. The hybrid frequency synthesizer uses a mixer to combine a reference frequency generated by a reference source and a DDFS output signal generated by a direct digital frequency synthesizer. The output from the mixer is then coupled to the input of a phase locked loop which multiplies the mixer output to generate the frequency synthesizer output.

Abstract: A system and method for transporting user-restricted data from a gateway device to a handheld viewing device is provided. The gateway device includes an information translator, content filters, and storage. The information translator delivers content from an information database coupled to the gateway to the handheld viewing device. A viewing component of the handheld device receives all possible data from the gateway device that the handheld device is capable of viewing. The user of the handheld device is then able to manually select certain portions of data through a user interface. Once the selection is complete, a series of comments are returned to the gateway device from the handheld device so that a subsequent viewing corresponds only to that information selected by the user.

Abstract: An adaptive noise suppression system includes an input A/D converter, an analyzer, a filter, and a output D/A converter. The analyzer includes both feed-forward and feedback signal paths that allow it to compute a filtering coefficient, which is input to the filter. In these paths, feed-forward signal are processed by a signal to noise ratio estimator, a normalized coherence estimator, and a coherence mask. Also, feedback signals are processed by a auditory mask estimator. These two signal paths are coupled together via a noise suppression filter estimator. A method according to the present invention includes active signal processing to preserve speech-like signals and suppress incoherent noise signals. After a signal is processed in the feed-forward and feedback paths, the noise suppression filter estimator then outputs a filtering coefficient signal to the filter for filtering the noise out of the speech and noise digital signal.

Abstract: A system and method for pushing information, such as calendar event messages, from a host system to a mobile data communication device upon sensing a triggering event is disclosed. A redirector program operating at the host system enables a user to continuously redirect calendar event messages, such as meeting reminders and notices, from the host system to the user's mobile data communication device upon detecting that one or more user-defined triggering events has occurred. The redirector program operates in connection with event generating applications and repackaging systems at the host system to configure and detect a particular user-defined event, and then to repackage the calendar event messages in an electronic wrapper prior to pushing the data items to the mobile device. An optimized data structure for storing the calendar event messages is also provided.

Abstract: A system and method for pushing information from a host system to a mobile data communication device upon sensing a triggering event is disclosed. A redirector program operating at the host system enables a user to continuously redirect certain user-selected data items from the host system to the user's mobile data communication device upon detecting that one or more user-defined triggering events has occurred. The redirector program operates in connection with event generating applications and repackaging systems at the host system to configure and detect a particular user-defined event, and then to repackage the user-selected data items in an electronic wrapper prior to pushing the data items to the mobile device.

Abstract: SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, conventional SAW expanders and compressors typically have insertion losses greater than 20 dB, which can have a profound effect on an RF link budget in a communication system. Insertion losses are drastically reduced by using a single phase unidirectional transducer (SPUDT-type) instead of a conventional IDT as a SAW expander/compressor. A SPUDT-type reflects SAW components which are lost in conventional IDT designs so that a stronger SAW is directed toward a transmission element. In a receiver, a SPUDT-type directs a stronger SAW toward a compressor IDT.