Abstract: A portable radio communication device (303) includes power control circuitry (315) for monitoring the voltage level incoming from a battery (317), and provides power to the rest of the radio communication device (303). The power control circuitry (315) includes a boost regulator (407) that is used to generate an internal reference signal for use throughout the radio communication device including an analog to digital converter (ADC) for digitizing the battery voltage for use by the power control circuitry (315). The power control circuitry (315) compares the digitized battery voltage to thresholds to control power to the remainder of the radio communication device (303). Additionally, a secondary comparator (413) is provided to prevent damage to the battery and radio communication device circuitry. The secondary comparator uses multiple undervoltage thresholds depending upon the power state of the radio communication device (303).

Abstract: The apparatus and method for high speed data and command transfer over an interface (202), such as an ISA or PCMCIA bus or interface, includes a transceiver (206) and a processor (210) having a direct memory access (DMA) controller (240), a memory (211) for storage of data, and a channel interface (218) for connection to a communications channel. The processor (210) is responsive through a set of program instructions, such as software or firmware, to receive an interrupt signal (310, 315) and, when the interrupt signal indicates a write command (320, 330), to transfer data via the transceiver from the interface to the memory for transmission over the communications channel (335), and when the interrupt signal indicates data received from the communications channel (350), the processor further responsive to generate a read command and transfer data from the memory to the interface via the transceiver (355).

Abstract: An apparatus for and method of checking the validity of one or more directory numbers in a device for interfacing communications equipment to a digital telephone line, wherein the device is capable of accessing at least two channels on the digital telephone line, each channel having a directory number associated therewith, including: instructing the device to establish a plurality of protocol layers; initiating a call from the device over a first channel of the digital telephone line to the device over a second channel of the digital telephone line only if the plurality of protocol layers are established; and determining if the call is received by the device over the second channel to check the validity of the directory number associated with the second channel.

Abstract: A radio communication device (103) operable in a radio communication system (100) providing a plurality of radio communication services including radiotelephone, facsimile and electronic mail services. The radio communication device (103) has a body housing element (107) and moveable housing element (109). When the moveable housing element (109) is in the closed position, the moveable housing element (109) covers a portion of a touch screen display (119). A keypad (125) is integrated into the moveable housing element (109) and operable when the moveable housing element (109) is in the closed position. When a user depresses a key of the keypad (125) a portion of the key provides pressure against the touch screen display (119). The provided pressure activates a portion of the touch screen display (119).

Abstract: A radio communication device (103) provides several radio communication services including radiotelephone service, electronic mail service, faxing service etc. . . . The radio communication device has a main body housing element (107) and a movable housing element (109), radio circuitry (113), a touch screen display (119), and a switch (127). In a closed position, the radio communication device (103) has a first set of limited radiotelephone functions such as phone number input and sending and receiving phone calls. In an opened position, the radio communication device (103) has a different set of user functions which include radiotelephone functions, advanced radiotelephone functions, and messaging functions. The switch (127) provides a signal responsive to the movable housing element (109) moving to the open position. Thus, switching the radio communication device (103) between a first set of user functions and the second set of user functions.

Abstract: The radio frequency transceiver was developed for use in a time division duplex (TDD) radiotelephone communication system. The transceiver includes a local oscillator which generates at least two local oscillator signals at different times. Each local oscillator signal has a unique frequency. During a first time period, the radio frequency transceiver receives a radio frequency signal. The first radio frequency signal is combined with one of the local oscillator signals, forming an intermediate frequency signal. During a second time period and substantially during the first time period, the transceiver generates a frequency offset signal. The frequency offset signal is combined with the second local oscillator signal, forming a second radio frequency signal. The intermediate frequency signal and the offset frequency signal are designed to have different frequencies to avoid the self-quieting problem inherent in a TDD communication system.

Abstract: An improved speech coder provides a more natural sounding replication of speech by modifying the mean-squared error criterion for the selected speech coder parameters. Specifically, the modification emphasizes the signal components that the speech coder has difficulty matching, i.e. the high frequencies. This emphasis is constrained to certain limitations to avoid over-emphasizing the speech.

Abstract: A radio communication device (50) has a housing having a first housing element (51) and a second housing element (53). The first housing element (51) is movable between an extended and a closed position. The radio communication device has at least two antennas (112, 113). A switch (121) is provided that is operable to switch between a first antenna (112) and a second antenna (113) responsive to position of the first housing element (51). Preferably the first antenna (112) is disposed in the first housing element (51) and the second antenna (113) is disposed in the second housing element (53) or a battery housing (57).

Abstract: A method for protecting information bits wherein input data bits, at least some of which are to be protected, are sorted based upon information determined from a subset of the input data bits. An error control coding technique is applied to at least some of the sorted bits. In the preferred embodiment, an input data stream of voice coder bits is separated into arrays of bits. A first array (302) comprises voice coder bits needing error protection, with the bits arranged in order of importance determined by voicing mode. The second array (303) comprises bits that will not be error protected. The bits from the first array are provided to the input of an encoder (304), then the encoded bits are combined (305) with the bits from the second array (303) to form a bit stream.

Abstract: The present patent application includes a discussion of an integrated information card reader. The card reader is integrated into a radiotelephone (101). The card reader has a set of electrical contacts imbedded in a sliding plate (205). The sliding plate (205) is coupled to at least a portion of the other electronic apparatus contained in the radiotelephone (101) and enhances the rigidity of the radiotelephone (101). The card reader also includes a cover plate (213). The cover plate (213) and the sliding plate (205) form a cavity for retaining an information card (105). The cover plate (213) has cantilevered springs (309, 313) shaped from its body for forcing the information card (105) against the first set of contacts (403) when the information card (105) is loaded. Additionally, the cover plate (213) provides shielding at least a portion of the electronic apparatus from electromagnetic and radio frequency interference (EMI, RFI).

Abstract: A radiotelephone (101) has a memory, a display (127) and a keypad (117) with at least one key (121) to produce at least a first function key signal and a second function key signal, and a plurality of data keys (119). First, a first function key creates a first function key signal, turning on the radiotelephone (209); second, a phone number is selected (215). Third, the first function key creates a second function key signal from said first function key, activating the radiotelephone to call the phone number (207). Fourth, a second function key creates a third function key signal disconnecting the radiotelephone from said call (211). Fifth, the second function key creates a fourth function key signal turning off the radiotelephone (213).

Abstract: The radio frequency (RF) shielding method uses RF shield clips. The RF shield clips have a base and two walls. The base is shaped to form two stabilizing legs for providing vertical stability. The two walls extend upward from the base, each wall has a portion flanged outward for accepting a portion of a RF shield. Each of the walls has multiple inwardly protruding domes for providing point contact to the RF shield.

Abstract: A digital speech coding method uses an Rth-order filter to model the frequency response of multiple filters, thereby, providing a filter which offers the control of multiple filters without the complexity of multiple filters. The Rth-order filter can be used as a spectral noise weighting filter or a combination of a short-term predictor filter and a spectral noise weighting filter, referred to as the spectrally noise weighted synthesis filter, depending on which embodiment is employed. In general, the method models the frequency response of L Pth-order filters by a single Rth-order filter, where the order R<L.times.P. Thus, this method increases the control of a speech coder filter without a corresponding increase in the complexity of the speech coder.

Abstract: An electrical connection between a balanced circuit, such as a radio receiver and an unbalanced circuit, such as an antenna requires a balun. In a small electronic device such as a radiotelephone, a traditional balun is impractical because of the physical constraints. The balun function is performed by using a transmission line of minimum transverse dimensions and a predetermined length between the receiver and the antenna.

Abstract: An amplifier contains an RF generated negative supply wherein the RF input of the negative generator is connected to the RF input of a first power amplifier stage. This arrangement allows the power supplies to be turned-on in the correct order, thus, avoiding any damage to the transistors or power supply. After the RF input turns on and the RF generated negative supply turns on, the power amplifier transistors are biased such that no current will flow from the drain to the grounded source. The power amplifier also features the ability to adjust the biasing voltage by increasing Vcontrol so that the bias current from the main supply can be controlled. Since the output power of the amplifier is monotonic with biasing current over the useful range of gate voltages, the output power can thereby be controlled by adjusting the control voltage. Additionally, the negative biasing voltage can be increased to the point where bias current from the main supply is at the correct level to achieve the desired output power.

Abstract: When a radio frequency (RF) circuit is integrated into a movable housing element of an electronic device one must consider the affects of the surrounding area when the RF circuit is in a functioning position. A preferred embodiment is a radiotelephone (100) having an antenna (105) integrated into a movable housing element (101). The antenna (105) has two functioning positions, an opened and a closed position. The antenna (105) is tuned for efficiency when the movable housing element (101) is in the opened position. When the movable housing element (101) is in the closed position, a first pair of conductive plates (107, 109) located in the movable housing element (101) and a second conductive plate (113) located in the second housing element (103) are positioned to retune the antenna (105) due to the detuning affects caused by the close proximity of other electronic components located in the second housing element (103).

Abstract: A transmission line has a limited cross-section, a transmission line geometry and an improved characteristic impedance tolerance. The transmission line geometry utilizes a unique combination of broadside coupling and coplanar coupling with a reflector plate in order to improve the tolerance of the characteristic impedance. First, a larger coplanar gap is used to reduce the etching error. Second, the inner dielectric thickness sensitivities were also reduced by relying on broadside coupling and coplanar coupling to determine the characteristic impedance of the transmission line. Third, the effect of registration error in the broadside coupling is eliminated by rendering the two signal bearing conductors on the same layer.

Abstract: A combined radiotelephone and paging device (101), hereinafter the combined unit, normally operates as a radiotelephone. In response to a predetermined condition, the combined unit operates as a paging device. The predetermined conditions include low battery voltage and poor communication channel quality or a request signal from a remote transceiver (109) of the radiotelephone system. The paging system and the radiotelephone system may be independent communication systems or they may be a single communication system. The combined unit (101) and its unique switching characteristics allows the combined unit (101) to utilize the paging devices beneficial qualities of lower power consumption and broader service range to enhance the usefulness of a radiotelephone.

Abstract: A mobile radiotelephone, and associated method, which facilitates usage thereof by a user while also operating an automotive vehicle. The radiotelephone includes a handset having actuation keys of unique geometries permitting the user to identify the keys by tactile rather than visual inspection. A visual-signal display assembly comprised of a heads-up display, including a screen element positionable at a front windshield assembly portion of an automotive vehicle, forms an output display of the radiotelephone, also to facilitate usage of the radiotelephone by a user while also operating the automotive vehicle.