Abstract: Disclosed are methods for acquiring a forward channel in a point-to-multipoint CDMA system. One method includes the steps of (a) despreading a received CDMA signal with a first pn code that is known to be present in the received CDMA signal and obtaining a first measure of received signal level; (b) despreading the received CDMA signal with a second pn code that is known not to be present in the received CDMA signal and obtaining a second measure of received signal level; and (c) synchronizing to a desired channel using a difference between the first and second signal levels. In this method the first step of despreading despreads a continuously transmitted side-channel, and the step of synchronizing synchronizes to the side-channel. Also, the step of obtaining a first measure of received signal level obtains a correlation peak, and the step of obtaining a second measure of received signal level obtains a correlation null.

Abstract: Users or subscribers of a spread spectrum synchronous communications system provide signals to the central station or base unit of that system, and receive signals therefrom. Proper synchronization among those users (and their signals) is needed to ensure proper operation of the system. To ensure proper synchronization among those users, the signal produced by each user is checked for presence and amount of any offset error. This is accomplished by using three despreaders for the signal for each user. For one such user, each such despreader for that user receives the spreading code for that user. However, the spreading code as received by any one such despreader is time-delayed with respect to the spreading code as received by the other two despreaders. Each such despreader receives the spreading code with a different amount of delay imposed on that spreading code. The outputs of the three despreaders are digitally combined (e.g. compared), or compared, to produce the offset estimate for that user.

Abstract: Disclosed are methods for acquiring a forward channel in a point-to-multipoint CDMA system. One method includes the steps of (a) despreading a received CDMA signal with a first pn code that is known to be present in the received CDMA signal and obtaining a first measure of received signal level; (b) despreading the received CDMA signal with a second pn code that is known not to be present in the received CDMA signal and obtaining a second measure of received signal level; and (c) synchronizing to a desired channel using a difference between the first and second signal levels. In this method the first step of despreading despreads a continuously transmitted side-channel, and the step of synchronizing synchronizes to the side-channel. Also, the step of obtaining a first measure of received signal level obtains a correlation peak, and the step of obtaining a second measure of received signal level obtains a correlation null.

Abstract: A gable top type paperboard carton for juices and other pourable product which may attack the integrity of seals is formed with a pour spout fitment attached to one of the two sloping roof panels. The carton is formed so as to exhibit a rectangular cross section transverse to its longitudinal (vertical) axis, to thereby yield a gable top whose sloping roof panels extend upwardly from the narrower carton side walls. In use, the consumer grasps the two widest side walls of the carton by the thumb and one or more other fingers. This is in distinction to grasping the narrower carton sides, which would entail a wider finger grasp or span. The carton includes a V pocket forming panel in a first gusset, the V pocket receiving a V forming point or wedge on the second gusset. A similar V forming pocket and V point may be located on opposite bottom closure panels. Either V forming pocket may be of paperboard or of barrier film.

Abstract: A detector circuit for indicating the chip rate of a direct sequence frequency hopped data transmission signal. The wide band input signal is channelized into L adjacent sub-bands and each sub-band signal is multiplied by a delayed copy of itself and then hard limited, after which all the hard limited product signals are totalized to give a resultant signal representative of the chip rate.

Abstract: A signal detector for receiving a wide band (W) of frequency-hopped signals which channelizes the incoming signals, via filter banks into a plurality (L) of channels. Magnitude squaring circuits in each channel generate a "power" estimate which is compared to a preset threshold value by threshold-quantizer units that produce a positive voltage (=1) if the threshold is exceeded. After summation of all the channels, the direct sequence (DS) signal component and noise component are processed so that a DC voltage is produced if a frequency-hop signal (FH) is present which is greater in value than when the signal is not present. Thus the DC signal indicates whether the FH signal is present or absent.

Abstract: A narrowband parameter estimator circuit is described which can be used to estimate the frequency and the relative power of narrowband interference tones which reside in a wideband information signal. A two-weight adaptive filter with a phase/frequency-lock loop circuit works in conjunction with a stepped synthesizer to lock onto the individual narrowband interference tones. A lock-detect circuit signals a digital logic unit to record the frequency of the stepped synthesizer and to measure the power in the adaptive filter output signal. This same output signal is used to cancel the unwanted tone in the wideband information signal being transmitted.

Abstract: A hop rate detector, for receiving frequency-hopped signals carrying information data, which generates a tone at the "hop rate" when modulated or unmodulated frequency-hopped signals are present. The input signal is channelized into sub-bands via filter banks and the signal in each channel is power detected (squared) and compared to a present threshold to produce a positive voltage (="1") if the threshold is exceeded and zero volts (="0") otherwise. The channel signals are split into an upper band (B.sub.u) and lower band (B.sub.d), then each band is summed and the lower band sum subtracted from the upper band sum to provide a first stage signal. The first stage signal has its DC component removed, then is multiplied by a delayed copy of itself to provide a frequency tone indicating the hop rate of the received signal.

Abstract: An I-Q channel adaptive line enhancer has bandpass filters with passbands that can be widened to well beyond the band that is actually being processed by the adaptive line enhancer. This eliminates the requirement of filtering one of the sidebands as is required in single channel adaptive line enhancers, in which the sum and difference sidebands are generated on up-conversion. Band limiting is done with lowpass filters, and the local oscillator may be made variable so that any part of the band that is passed by the bandpass filters can be processed by a single I-Q channel adaptive line enhancer. This type of I-Q channel adaptive line enhancer can process any one of a large number of possible bands without tunable bandpass filters, or without banks of adaptive line enhancers which have been preset to adjacent sub-bands.

Abstract: The reference channel, the narrowband channel, and the error feedback channel are all constructed with analog components, while the adaptive processor is constructed with digital components. Unavoidable analog time delays in the narrowband and the error feedback channels are compensated for in the digital adaptive processor. The adaptive line enhancer described herein employs a local oscillator signal which is mixed with the input signal in a reference channel, which is subsequently converted to a digital signal. A digitized reference signal is supplied to an adaptive filter as an input signal. The adjustable weight values of the adaptive filter are adjusted by a feedback digitized signal. The output signal is derived from the subtraction of a narrowband analog signal, which is derived from the adaptive filter. The error feedback signal is split off of the output signal, mixed with the local oscillator signal, and supplied to the weight update mechanisms.

Abstract: The weights of least mean square (LMS) adaptive filter are updated with a different set of taps than are used to form the output of the adaptive filter in the adaptive processing device of the present invention. As a result of performing the multiplications and sums required for the filter operation simultaneously, an integral number of clock cycle delays appear in the narrowband and error feedback channels. The number of taps of the tapped delay line of the invention are increased, whereby the increased delay through the delay line may be used to compensate for a delay through the filter of an integral number of clock delay cycles. Instantaneous weight updating in accordance with the signal being utilized, may then be achieved at a clock rate frequency that is ten times or more greater than prior art adaptive filters.