Abstract: A interface device and a method of allowing communication is provided to allow a wireless mobile communications device to interface with a satellite communication system. The interface includes a satellite modem (including antenna), a communications link to communicate with the wireless communications device (such as a Wifi link using VoIP) and an applications processor (with associated memory) to handle control and handshaking functions between the communications link and satellite modem and the related interfaced equipment (mobile communications device and satellite system) and to assist and reformat as needed transmission of data between the interfaced equipment.

Abstract: An asset locator device including (a) a wireless receiver capable of receiving an identifier signal transmitted from a short range wireless transmitter device; (b) a wireless transmitter capable of transmitting a message to a space based network; (c) a positioning system capable of determining the location of the locator device; (d) a vibration sensor; and (e) a controller. The controller instructs the asset locator to: (i) attempt to detect the identifier signal from the transmitter device if the vibration sensor senses vibration; and (ii) transmit a signal, including an asset location, to the space based network if: (1) the identifier signal is not detected; and (2) location fixes from the positioning system indicate a location change of the asset.

Abstract: A asset group tracking system which includes a plurality of solar powered tracking devices on separate assets. Each of the tracking devices further includes: (i) a Global Navigation Satellite System (GNSS) receiver; (i) a transceiver; (iii) a processor controlling the GNSS receiver and transceiver; (iv) a rechargeable battery powering one or more of the GNSS receiver, the transceiver, or the processor; and (v) a solar power collector for charging the battery. In the system, a minority of the tracking devices further include a satellite transmitter.

Abstract: An asset locator device including (a) a wireless receiver capable of receiving an identifier signal transmitted from a short range wireless transmitter device; (b) a wireless transmitter capable of transmitting a message to a space based network; (c) a positioning system capable of determining the location of the locator device; (d) a vibration sensor; and (e) a controller. The controller instructs the asset locator to: (i) attempt to detect the identifier signal from the transmitter device if the vibration sensor senses vibration; and (ii) transmit a signal, including an asset location, to the space based network if: (1) the identifier signal is not detected; and (2) location fixes from the positioning system indicate a location change of the asset.

Abstract: A device (10) for determining the movement or elongation of an article, particularly a belt (28), is disclosed. The device (10) is comprised of two different pitched length scales (12, 14) which when laid upon one another form a vernier scale. When the scales are laid upon one another, a small area of visible contrasting color (24) is seen. A large movement of the visible contrasting color (24) indicates the miniscule movement of either scale (12, 14), relative to the other. The device (10) disclosed may also be partially imprinted onto a belt (28) wherein minute elongation of the belt (28) is obvious.

Abstract: An endless belt (10) for use in exercising treadmills is provided. The endless belt includes at least an underlying ply (18) of low friction material, an internal core (38) of compressive and resilient material, and an overlying skin (42) of abrasion resistant material. The internal core (38) consists of a series of transverse projections (30) having inclined side walls (46, 47). The shape of projections (30) of the internal core (38) allows for the compression thereof while providing a suitable walking/running surface. The underlying ply (18) minimizes friction between the belt and any underlying support. The overlying skin (12) increases the durability of the belt while providing friction between a user's foot and the belt (10) for movement thereof. The belt may further include a reinforcing ply (32) disposed between the underlying ply (18) and the internal core (38).

Abstract: An analog-to-digital converter having adaptable quantizing levels which compensate for unintended variations in the analog input signal amplitude. Variations in the amplitude range over which the quantizing levels extend is determined from an examination of preselected bits of the analog-to-digital converter output.

Abstract: Each multiply-accumulate device, in an adaptive equalizer, multiplies each input signal sample by an associated coefficient in an ensemble, stores the result and periodically outputs the accumulated results as the equalized input signal. A rotating coefficient register in the adaptive equalizer successively associates each coefficient in the ensemble with a different multiply-accumulate device. Coefficient update circuitry is also provided which periodically updates the coefficients in the ensemble so as to optimize equalizer performance.

Abstract: A technique is disclosed for equalizing an incoming signal including quadrature-related carrier signals by forming the product of the incoming signal at at least one prescribed time and only one real-valued coefficient associated with each time. In one embodiment of the present invention, the equalized incoming signal is demodulated into a first pair of component signals. At least one of these component signals is then used to generate each coefficient. In another embodiment of the present invention, each coefficient is generated in response to at least one of the component signals in the first pair along with a second pair of component signals which are formed by demodulating the incoming signal. This technique can be advantageously adapted to incorporate a number of coefficient updating algorithms and is suitable for use in a number of modulation formats.

Abstract: A technique is presented for simplifying the recovery of two synchronous data signals having a common symbol rate after each signal has respectively modulated a different one of a pair of quadrature-related carrier signals. In the transmitter, the data signal which modulates one of the quadrature-related carrier signals is delayed relative to the data signal which modulates the other quadrature-related carrier signal. This delay is related to an IF frequency chosen at the receiver. After passing through a noisy transmission channel, the quadrature-related carrier signals are coupled in the receiver to a serial combination of an equalizer and analog-to-digital converter. This combination outputs multiple, substantially distortion-free samples of the data signals each symbol interval. The two data signals are then recovered by selecting a subset of the samples provided each symbol interval.

Abstract: A technique for digitally synthesizing the amplitude modulation of one or more carrier signals with a random digital data signal is disclosed. Pursuant to the present invention, a memory unit is addressed by a plurality of binary coded digital symbols in the data signal. For each address, at least two digital representations are read out. Each representation corresponds to a different sample of the carrier signals which has been amplitude modulated by a composite of the spectrally shaped data signal. The disclosed technique can be adapted to synthesize a variety of modulation formats, and can provide compensation for fixed in-rail and cross-rail distortions.

Abstract: A technique is disclosed for improving the recovery of data signals transmitted on orthogonally polarized carrier signals by creating redundancy with respect to timing and carrier information. In the receiver, the carrier and timing recovery circuitry, which controls the recovery of the data signals from the incoming orthogonally polarized carrier signals, operate in response to a selected one of the carrier signals or at least one data signal recovered from this selected carrier signal. This selection is based on an examination of the data signals recovered from each of the orthogonally polarized carrier signals. Use of the described technique advantageously lessens the possibility of the carrier and timing recovery circuits losing synchronous operation during fading as it is less likely that a fade will simultaneously affect both orthogonally polarized carrier signals. As a result, data signal recovery is improved.

Abstract: A digital synthesis technique provides pulse shaping in accordance with predetermined time domain and frequency domain constraints. In the technique, the informational content of a binary bit stream is used by an access circuit (12) to form address words for accessing a read-only-memory (13). The digital representations stored in the ROM (13) represent a superposition of temporally-displaced truncated impulse time functions, each weighted by the discrete transmission symbol levels of the analog output signal. The digital representations from two ROMs (13-1 and 13-2) are toggled by a sequencng circuit. In other embodiments of the invention, different memory arrangements ranging from a signal ROM (142) to an array of ROMS (163-1 through 163-3 and 164-1 through 164-3) are respectively used to decrease circuit complexity. In a digital radio transmission application of the technique, this arrangement is economical, readily reproducible and stable since it obviates the need for conventional complex analog filters.

Abstract: An adaptive timing technique is disclosed for adjusting the sampling times of a received digital signal for fewer regeneration errors. In accordance with the disclosed technique, a sequence of digital signal samples is formed and an error signal is generated by comparing a selected sample in the sequence to a threshold. The sampling times of subsequently formed samples are then altered in response to the sample sequence and error signal only when the sample values in the sequence are successively increasing or decreasing.

Abstract: A fractionally spaced adaptive equalizer is disclosed wherein the coefficients (C.sub.-2 to C.sub.+2) are updated synchronously by an integral -T error circuit (40) and alternately by a fractional =T error circuit (48). This arrangement features a single unique minimum for the adaptive structure thereby preventing the coefficient drift to very large values so coefficient tap leakage is not required to minimize coefficient values. The adaptive characteristic is well suited for linearly dispersive channels, such as exhibited during terrestrial radio transmission during tropospheric multipath propagation. The inventive principles are broadly applicable to any of the well known algorithms for adapting digital filters. A configuration of fractionally spaced equalizers (70.sub.1 -70.sub.4) provides the benefits of Nyquist-rate coefficient updating for a dual rail quadrature amplitude modulated (QAM) signal application.