Abstract: A method is disclosed for performing a discrete cosine transform on a transform input value wherein the discrete cosine transform has a plurality of predetermined transform coefficients. A number N.sub.1 of shift operations is determined independently of the transform input value in order to provide a set of N.sub.1 of shift operations. A number N.sub.2 of add operations is determined independently of the transform input value in order to provide a set of N.sub.2 add operations. The transform input value is operated upon only by the N.sub.1 shift operations and the N.sub.2 add operations to provide a discrete cosine transform output value without any multiplication. This method may be applied to both forward and inverse discrete cosine transforms. The transform coefficients are simplified coefficients which are provided by truncating and modifying prior art transform coefficients.

Abstract: An instruction caching system comprises meta-instructions which are contained within the program being executed. A meta-machine, which is a small segment of software, executes the meta-instructions and passes control to the processor itself at appropriate times to execute blocks of instructions from the instruction cache.

Abstract: An improved method and system for instructing individuals as to the various breeds of animals and in the art of exhibition. An event board simulates true life circumstances which occur while exhibiting during a competition. Other devices are employed which instruct users as to the various aspects of exhibition and of dog breeds such that the information is presented in a manner which is enjoyable to the users. The game board indicia is presented in tracks or bands, with each band representing a different level of competition.

Abstract: An improved method of doppler searching in a digital GPS receiver is described. According to the principles of the present invention, an N-point fourier transform is performed on samples of a down converted GPS signal representing the entire range of Doppler-shifted GPS carrier frequencies. The magnitude of the square of each of the output samples is calculated to produce N power quantities, corresponding to N search frequencies. The power quantities for each of the N search frequencies are then summed to produce N quantities proportional to average power. The maximum of the N-power quantities indicates the presence of the corresponding GPS signal.

Abstract: A digital FM demodulator is described. According to the principles of the present invention, a digital FM signal is demodulated by processing sampled input vectors of a quadrature FM digital signal centered approximately zero frequency. The sampled quadrature input vectors are quantized to lie within a predetermined magnitude range. The quantized vectors are coupled to a phase accumulator which generates a current coarse phase value related to input vectors of the quadrature FM signal. The output of the phase accumulator is also coupled to a vector rotation means which rotates the input vector to a predetermined quadrant to determine a fine phase value based on said rotated input signal vector. The fine and coarse values are then summed and output as a composite phase value, and digitally filtered by subtracting the value of the previous composite phase angle sample from the value of the current composite phase angle sample to produce a demodulated message sample.

Abstract: A dispatch trunked radio system which provides duplex or simplex telephone interconnect communications to subscriber units is described. The system allows duplex capable trunked system subscriber units to establish a full duplex communication link with conventional land based telephone interconnect service in accordance with a method which unifies the operation of the trunked system subscriber units, a plurality of trunked system repeaters, a trunked system central control unit, and a telephone interconnect control unit. The method of the present invention also provides improved trunked system performance by allowing simultaneous transmission and reception of channel controlling information.

Abstract: A method and means for improving the frequency resolution in a digital oscillator is described. According to the principles of the present invention, a digital oscillator may be comprised of a frequency latch, a phase accumulator, and a ROM based waveform generator. Improved frequency resolution is achieved in the digital oscillator, without increasing ROM size by quantizing the summed output of a dither generator and the phase accumulator before sending the resultant multi-bit signal to a ROM. The contents of the ROM are sequentially addressed with the resultant multi-bit signal. The output of the ROMs comprise digital words corresponding to a desired waveform envelope.

Abstract: A method and means for quadrature amplitude modulation is described. The improved QAM modulator circuit utilizes a small read only memory to hold multiple versions of a signal constellation resulting in the elimination of hardware modulator circuits. In addition, the described device can be potentially any modulation scheme on an input signal which is sampled in time by modifying the contents of said ROM.

Abstract: An improved mounting system for surface mounted components is described. The mounting system of the present invention provides preparations for surface mounted components and the printed circuit substrate which render the resultant assembly highly resistant to stresses which occur due to thermal cycling. The printed circuit substrate is conditioned by removing selected areas of media surrounding the points of attachment between the surface mounted component and the printed circuit media. In addition, a spacing element is disposed between the surface mounted component and the printed circuit media to promote the formation of a virtual lead during assembly.

Abstract: A method and means for reducing noise in a GaAs FET oscillator circuit is described. The circuit of the present invention achieves low noise oscillator operation by driving the gate input of the GaAs FET oscillator circuit with a source of voltage which exhibits a low impedance at baseband frequencies and driving the drain input with a source of current which exhibits a high impedance at said frequencies. The present invention further operates to control the D.C. voltage present on the drain terminal of the GaAs FET device regardless of the drain current, while simultaneously maintaining a constant D.C. drain current at some predetermined value which corresponds to optimum low-noise operation.

Abstract: A digital lock detector for a phase-locked loop accumulates out-of-lock pulses which are derived from a high frequency clock signal. The out-of-lock pulses are gated by an out-of-phase indicator signal and a pulse centered around the phase-locked loop output cycles to reduce the effect of relative phase jitter between the input and output signals of the phase-locked loop. The digital lock detector utilizes two counters in series which are reset independently to provide resistance to fading signal conditions. In addition, the lock detector circuit requires several consecutive long out-of-lock indications before an out-of-lock condition is indicated.

Abstract: A method and means for controlling telephone interconnect traffic on a trunked radio system is described. The present invention continuously monitors all types of communication traffic on the system and in response to an increasing dispatch access delay, reserves certain repeaters for dispatch use only during a predetermined period. The present invention also contemplates a system in which the number of simultaneous telephone interconnect calls permitted on the system during a predetermined period is dynamically altered in response to system loading. In addition, the present invention establishes a variable, periodically updated, maximum interconnect call length based on the current system dispatch access delay.

Abstract: An improved simulcast transmission in which a signal transmitted by a master station provides a reference frequency signal, as well as a voice and data path, is described. The system can be configured such that a master station can transmit AFSK data and voice or FSK data and voice. In either case, the remote transmitter will retransmit FSK and voice.

Abstract: Method and apparatus are provided for control of a dedicated data slot in a time-division multiplex system for both voice and data communications enabling equal access to the data slot, efficient data throughput and reliability.

Abstract: A paging station remote control system encoder is described. The paging system encoder generates signals in accordance with a predetermined signalling scheme comprising a series of tones and timed pauses and generated in response to control signals supplied either manually or by a paging terminal. The paging system encoder provides control signals which instruct a paging transmitter station to key in the analog or binary modulation mode or to switch from one mode to another without first dekeying the paging transmitter.

Abstract: An improved analog CMOS comparator circuit is described. The improved circuit incorporates an additional CMOS device in the output stage of a conventional differential comparator. The additional device compensates for current imbalances which occur at relatively high common mode voltages thus allowing the improved comparator to operate over a wider range of common mode input voltages.

Abstract: A circuit and technique for directing an adaptable antenna system is described. The invention is coupled to the output of an RF receiver configured to provide a data signal output, and evaluates the quality of the receiver data signal. The invention switches antennas when the signal quality deteriorates below a predetermined level.

Abstract: An adaptable homotropic antenna system for use with a portable communication transceiver is described. The antenna system can be used for reception or transmission and can be completely enclosed within the portable transceiver housing. The homotropic antenna system evaluates the quality of a received signal and if the signal is below a predetermined threshold level, an alternate antenna will be selected. The antenna system will continue to sample the available antennas until an antenna produces a signal of acceptable quality.

Abstract: A programmable bias circuit for use with a data limiter circuit is described. The limiter and bias circuit are coupled to a portable data receiver which is adapted to communicate in a coded system. Frequency disparities between a transmitted word sync signal and the portable data terminal local oscillator signal will cause a DC offset voltage in the received data signal. The programmable bias circuit is controlled by a decoder within the portable data terminal. If the terminal is in an idle state, the programmable bias circuit will be set to rapidly follow offset voltage shifts until a transmitted word sync signal has been detected. After word sync has been detected, a slower, more stable time constant circuit is programmably activated for the duration of the digital data message. The fast time constant circuit is activated at the end of the received data signal.