Abstract: A system is provided that can introduce data redundancy into wireless communications, and in particular ultra-wideband (UWB) wireless communications to increase the communication range when transmitting data that has low transmission rates. Multipath degradation, introduced by the extended communications range, can be mitigated by frequency hopping between the orthogonal frequency-division multiplexed symbols of the ultra-wideband waveform. Frequency hopping can place adjacent symbols in different frequency channels for filtering. Data redundancy can be expanded in the time domain and/or the frequency domain, resulting in extended range.

Abstract: A system is provided that can introduce data redundancy into wireless communications, and in particular ultra-wideband (UWB) wireless communications to increase the communication range when transmitting data that has low transmission rates. Multipath degradation, introduced by the extended communications range, can be mitigated by frequency hopping between the orthogonal frequency-division multiplexed symbols of the ultra-wideband waveform. Frequency hopping can place adjacent symbols in different frequency channels for filtering. Data redundancy can be expanded in the time domain and/or the frequency domain, resulting in extended range.

Abstract: A system is provided that can introduce data redundancy into wireless communications, and in particular ultra-wideband (UWB) wireless communications to increase the communication range when transmitting data that has low transmission rates. Multipath degradation, introduced by the extended communications range, can be mitigated by frequency hopping between the orthogonal frequency-division multiplexed symbols of the ultra-wideband waveform. Frequency hopping can place adjacent symbols in different frequency channels for filtering. Data redundancy can be expanded in the time domain and/or the frequency domain, resulting in extended range.

Abstract: A system is provided that can introduce data redundancy into wireless communications, and in particular ultra-wideband (UWB) wireless communications to increase the communication range when transmitting data that has low transmission rates. Multipath degradation, introduced by the extended communications range, can be mitigated by frequency hopping between the orthogonal frequency-division multiplexed symbols of the ultra-wideband waveform. Frequency hopping can place adjacent symbols in different frequency channels for filtering. Data redundancy can be expanded in the time domain and/or the frequency domain, resulting in extended range.

Abstract: A system is provided that can introduce data redundancy into wireless communications, and in particular ultra-wideband (UWB) wireless communications to increase the communication range when transmitting data that has low transmission rates. Multipath degradation, introduced by the extended communications range, can be mitigated by frequency hopping between the orthogonal frequency-division multiplexed symbols of the ultra-wideband waveform. Frequency hopping can place adjacent symbols in different frequency channels for filtering. Data redundancy can be expanded in the time domain and/or the frequency domain, resulting in extended range.

Abstract: A system is provided that can introduce data redundancy into wireless communications, and in particular ultra-wideband (UWB) wireless communications to increase the communication range when transmitting data that has low transmission rates. Multipath degradation, introduced by the extended communications range, can be mitigated by frequency hopping between the orthogonal frequency-division multiplexed symbols of the ultra-wideband waveform. Frequency hopping can place adjacent symbols in different frequency channels for filtering. Data redundancy can be expanded in the time domain and/or the frequency domain, resulting in extended range.

Abstract: A technique for determining the time of arrival of a signal includes generating a spread spectrum signal with a number of code sectors, each including a periodic sequence of spread spectrum chips that corresponds to a predetermined correlation function. The periodic sequences of chips of the code sectors are shifted in time by differing amounts relative to a periodic time reference. Upon reception, the spread spectrum signal is periodically sampled, and the different code sectors produce different sampling points on the correlation function such that a number of time-shifted correlation functions results from time shifts of the code sectors. The time of arrival of the spread spectrum signal can be determined by curve fitting of the sampling points from the set of time-shifted correlation functions.

Abstract: A method is described of pulse shaping a modulated sequence spread signal having serially formatted in-phase (I) and quadrature (Q) waveforms, each waveform includes a predetermined number of chips per symbol.

Abstract: Methods and apparatus for synchronization (SYNC) detection of a received serial offset quadrature pulse shaped waveform modulated by a symbol SYNC sequence are provided. The waveform is serially demodulated into a serial baseband signal and serially correlated with segments of the symbol SYNC sequence. Correlation strength estimates of each of the serially correlated output signal are computed and combined to detect a coarse SYNC. The serially correlated output signals are phase corrected based upon phase change conditions and the phase corrected signals are used to detect a fine SYNC.

Abstract: Methods and apparatus for determining carrier frequency error of a serial offset quadrature pulse shaped signal, such as a minimum shift keyed (MSK) signal, are disclosed. Carrier frequency error is determined by receiving a quadrature pulse shaped signal having a synchronization sequence, detecting synchronization of the quadrature pulse shaped signal, and storing a baseband inphase (I) signal and a baseband quadrature (Q) signal of the synchronization sequence while detecting synchronization. After detecting synchronization, segments of the stored baseband I and Q signals are read and correlated with a spreading sequence. Carrier frequency error is then estimated based on phase differences between each of the correlated segments.

Abstract: A method of correcting phase error of a phase shift keyed (PSK) signal includes (a) receiving a signal modulated by a spreading sequence; (b) despreading the received signal using a receiver spreading sequence similar to the spreading sequence of step (a); (c) calculating a crosscorrelation profile between the receiver spreading sequence and the received signal; and (d) calculating an autocorrelation profile of the receiver spreading sequence to determine a spreading code property (SCP). The method also includes (e) estimating a timing error in alignment between the autocorrelation and the crosscorrelation profiles; and (f) correcting a phase error of the signal despread in step (c), by using the SCP and the estimated timing error.

Abstract: A technique for determining the time of arrival of a signal includes generating a spread spectrum signal with a number of code sectors, each including a periodic sequence of spread spectrum chips that corresponds to a predetermined correlation function. The periodic sequences of chips of the code sectors are shifted in time by differing amounts relative to a periodic time reference. Upon reception, the spread spectrum signal is periodically sampled, and the different code sectors produce different sampling points on the correlation function such that a number of time-shifted correlation functions results from time shifts of the code sectors. The time of arrival of the spread spectrum signal can be determined by curve fitting of the sampling points from the set of time-shifted correlation functions.

Abstract: An automated cassette loader system includes a front loading tape drive mounted in a standard height enclosure with a removable magazine including cassettes stored in front to rear alignment in two levels. The cassettes are pushed between entry and exit positions by pushing one cassette out of a push position in one level and then pushing a cassette from a push position in the other level. The cassette pushed out of the magazine is transported to the front loading tape drive and, when removed therefrom, transported to the intake of the other level of the magazine.

Abstract: A mechanical interlocking is provided between a bidirectional swinging access door with a moveable part of a tape cassette or magazine loading mechanism such that the door remains unlatched as the moveable part moves from its forward loading/unloading position to its rearward operational position and the door remains latched as the moveable part moves in the forward direction from its operational position to its loading/unloading position.