摘要:
Apparatus for fine positioning a tape head relative to a head carriage that is coarsely positionable by a lead screw. The fine positioning apparatus includes parallel first and second resilient support beams oriented generally parallel to the direction of tape travel and having their ends fixedly secured to the head carriage so as to be deflectable in a direction transverse to the direction of tape travel. The centers of the parallel first and second support beams have their centers secured to a tape head frame which contains the tape. A linear motor drives the tape head frame against the resilience of the first and second resilient support beams in response to a drive signal which, for example, is derived from tracking error information produced pursuant to reading of servo information on tape. Pursuant to the displacement of the tape head frame against the resilience of the support beams, the magnetic tape head is moved along a linear path transverse to the tape travel direction. For operation with tapes without servo information on tape, a piezoelectric transducer detects the deflection of one of the support beams and provides an output which is utilized to provide damping of the natural resonance the spring/mass system that includes the first and second resilient support beams and the tape head and tape head frame supported thereby. Alternatively, the operation with tapes without servo tracks can be open-loop with the damping being provided by damping members disposed symmetrically on either side of the tape head frame.
摘要:
Tape head positioning apparatus that includes a head carriage frame and a parallel beam positioning structure supported by the head carriage for supporting the magnetic tape head and for variably positioning the magnetic tape head relative to the carriage along a path generally transverse to the tape travel direction. The parallel beam positioning structure includes parallel support beams secured at their ends to the head carriage. The magnetic tape head is secured between the bender beam at a location generally between their ends. In a particular embodiment of the parallel beam positioning apparatus, the parallel support beams comprise first and second resilient reed beams having their ends secured to the head carriage and configured to be deflectable in a direction transverse to the tape travel direction. A voice coil linear motor deflects the reed beams pursuant to a control signal to move the magnetic tape head along the path transverse to the tape travel direction. In a further embodiment of the parallel beam positioning apparatus, the support beams comprise first and second parallel piezoelectric bender beams having their ends secured to the head carriage and configured to deflect in a direction transverse to the tape travel direction in response to a control signal. Deflection of the bender beams pursuant to the control signal displaces the magnetic tape head along the path transverse to the tape travel direction.
摘要:
A notch filtering apparatus comprises an input configured to receive at least one cellular code division multiple access (CDMA) signal. Each received cellular CDMA signal has an associated spread bandwidth. A notch filter device is configured to attenuate a bandwidth at a plurality of frequencies within the associated spread bandwidth of the at least one received cellular CDMA signal.
摘要:
A system and method for encoding and transmitting data with a spread-spectrum packet-switched system. Data to be transmitted by a packet transmitter are encoded for privacy and to restrict intelligent receipt of the data to the intended recipient. The encoded data is demultiplexed into sub-data-sequence signals which are spread-spectrum processed and then combined as a multichannel spread-spectrum signal. The multichannel spread-spectrum signal is concatenated with a header to output a packet-spread-spectrum signal which is transmitted over radio waves to a packet receiver. The packet receiver obtains timing for the multichannel spread-spectrum signal from the header. The multichannel spread-spectrum signal is then despread and multiplexed as received-encoded data. The received-encoded data is decoded by the intended recipient and stored in a receiver memory for output.
摘要:
A spread spectrum base station comprises an automatic gain control (AGC) circuit having an input configured to receive a received spread spectrum signal and gain control the received spread spectrum signal to produce a gain controlled signal. A correlation circuit has an input configured to receive the gain controlled signal and correlate the gain controlled signal with a code to produce a despread signal. A power measurement and comparator circuit is configured to receive the despread signal and a control level of the AGC circuit. The circuit processes at least the despread signal and the control level to produce a processed signal and compares the processed signal with a threshold to produce a comparison signal. The comparison signal is used to produce a power command. A multiplexer multiplexes the power command with a signal for transmission over an antenna.
摘要:
A system and method for encoding and transmitting data with a spread-spectrum packet-switched system. Data to be transmitted by a packet transmitter are encoded for privacy and to restrict intelligent receipt of the data to the intended recipient. The encoded data is demultiplexed into sub-data-sequence signals which are spread-spectrum processed and then combined as a multichannel spread-spectrum signal. The multichannel spread-spectrum signal is concatenated with a header to output a packet-spread-spectrum signal which is transmitted over radio waves to a packet receiver. The packet receiver obtains timing for the multichannel spread-spectrum signal from the header. The multichannel spread-spectrum signal is then despread and multiplexed as received-encoded data. The received-encoded data is decoded by the intended recipient and stored in a receiver memory for output.
摘要:
A system and method for transmitting a plurality of spread-spectrum signals over a communications channel having fading. The plurality of spread-spectrum signals are radiated by a plurality of antennas, with each antenna preferably spaced by one-quarter wavelength. A plurality of receiver antennas receive the plurality of spread-spectrum signals and a plurality of fading spread-spectrum signals. Each receiver antenna is coupled to a plurality of matched filters having a respective plurality of impulse responses matched to the chip-sequence signals of the plurality of spread-spectrum signals. A RAKE and space-diversity combiner combines, for each respective chip-sequence signal, a respective plurality of detected spread-spectrum signals and a respective multiplicity of detected-multipath-spread-spectrum signals, to generate a plurality of combined signals. The symbol amplitudes can be measured and erasure decoding employed to improve performance.
摘要:
A first access number stored on the removable computer chip module is retrieved by a mobile cellular device. The first access number to a cellular network is transmitted by the mobile cellular device using spread spectrum communications. The mobile cellular device receives a second access number in response to the cellular network allowing the mobile cellular device access. The mobile cellular device transmits the second access number to the cellular network using spread spectrum communications for subsequent access to the cellular network.
摘要:
A spread spectrum signal is received. The received spread spectrum signal is despread using a reference code signal, as a despread reference code signal. The received spread spectrum signal is despread using at least one message code signal, as at least one despread message code signal and using the despread reference code signal as a phase reference for the despreading of the received spread spectrum signal using the at least one message code signal. Data from the at least one despread message code signal is recovered.
摘要:
An improvement to a transceiver, such as a cell phone, a palm pilot, or equivalent telephone or computer display device, comprising a plurality of display devices, expanding supports, and a screen-size indicator. The expanding supports are connected to the transceiver, such as a cell phone, palm pilot or computer, and to the plurality of display devices. The expanding supports expands the plurality of display devices about the transceiver, such as a cell phone. The screen-size indicator is connected to the plurality of display devices. The screen-size indicator displays the video signal on the transceiver, such as a cell phone display, or the plurality of display devices, or the combination of the transceiver, such as a cell phone, palm pilot or computer, display and the plurality of display devices, as determined by the screen size, respectively.