Abstract: A method and apparatus for implementing a discrete cosine transform (DCT) or an inverse DCT (IDCT) with a single hardware unit which applies only positive valued multiplicative coefficients and can be switched to either perform a DCT or an IDCT. The invention processes parallel input digital data signals to produce parallel output digital data signals which represent a discrete transform (either a DCT or an IDCT) of the input data. One aspect of the invention is a method and apparatus for performing discrete transforms using a multiplier which implements MSB-first, bit-serial, carry-save, multiplication of an input word by a positive fixed coefficient. In one class of embodiments, the serially received digits of the input word can take on positive values only. In other embodiments, the serially received digits of the input word can take on positive or negative values.

Abstract: In a digital wireless communication system communicating between a mobile unit and a stationary unit, a received digitally encoded signal is sampled to produce a first sampled digital signal having a plurality of symbols. The short term energy over a plurality of a contiguous symbols is measured. The short term energy symbol over a first plurality of a contiguous short term energy points is measured. The short term energy average over a second plurality of contiguous short term energy points is measured. The second plurality of contiguous short term energy points is spaced apart from the first plurality of contiguous short term energy points. The difference between the first short term energy average and the second short term energy average is calculated to derive an estimate of the speed of the mobile unit relative to the base unit.

Abstract: An equalization method for digitally encoded signals transmitted in a plurality of non-contiguous time slots has a digitally encoded synchronization signal commencing in each time slot followed by a digitally encoded data signal having a digitally encoded marker signal at a predetermined time period. The synchronization signal of the assigned time slot ("first synchronization signal") and the digitally encoded data signal of the assigned time slot including the marker signal, and the digitally encoded synchronization signal of the immediately succeeding non-assigned time slot ("second synchronization signal") are all stored. The location of the minimum energy point of the stored digitally encoded signals is determined. Equalization is performed starting from the first synchronization signal to the minimum energy point. Then, the equalization commences from the second synchronization signal backwards until the minimum energy point is reached.

Abstract: In a digital wireless communication system, a first unit transmits a digitally encoded signal to a second unit in a plurality of non-contiguous time slots. Within each time slot, the digitally encoded signal has a synchronization signal portion followed by a data signal portion. The second unit has an antenna to receive the synchronization signal portion of the digitally encoded signal. The second unit also has a clock to generate a clock signal at a first rate having a sampling phase. An analog to digital converter receives the clock signal and the synchronization signal and samples the synchronization signal at the first rate to generate a first plurality of symbols. An interpolator receives the first plurality of symbols and interpolates the first plurality of symbols to generate a second plurality of symbols at a second rate. The second rate is a multiple of the first rate.

Abstract: In the present invention a wireless communication system is disclosed. A base unit communicates with a remote unit. The system comprises means for transmitting, using CDMA, between the base unit and the remote unit, in one of a plurality of frequencies channels selected. In one period of time, the base unit transmits and in another period of time, different from the one period, the remote unit transmits. Further, the system comprises means for changing the one frequency channel selected to another frequency channel, different from the one frequency channel, in response to interference in the one frequency channel. Thus, communication between the base unit and the remote unit is then affected over the another frequency channel.

Abstract: A method and apparatus for converting input image data in line-scan format into block-scan format, and for converting input image data in block-scan format into line-scan format. The apparatus can be implemented as a single integrated circuit which includes a memory and control logic for implementing format conversion, but no external address lines. The apparatus includes an address generator which automatically generates an address sequence for each strip of input data. Each input data strip comprises N lines of image data words, with L vectors in each line, where each vector comprises M image data words. The apparatus converts a line-scan format input data strip into blocks each consisting of N vectors. Each input data strip is processed efficiently, by automatically generating a sequence of addresses for the vectors of the strip.

Abstract: A divide circuit having bit level pipeline capability uses an array of bit level carry save adders with each carry save adder having a corresponding absolute value bit level circuit. In one or two's complement notation, the carry save adders subtract the binary values supplied thereto and generates an intermediate binary signal which is supplied to the absolute value circuit. The absolute value circuit determines the absolute value of the binary number supplied thereto. The circuit performs division in accordance with the following algorithm:Q.sub.w 1I=W-1 to 0N=N-DS=Signbit (N)Q.sub.I =S (EXOR) Q.sub.I+1N=.vertline.N.vertline.D=D/2ENDA recursive divide circuit employing an array of carry save adders and absolute value bit level circuits achieves full pipeline bit level capability.

Abstract: In the present invention, the power of a remote transmitted signal is controlled, by a remote communication device. The remote communication device is in communication with the base communication device. The base communication device transmits to the remote device a base transmitted signal. The base transmitted signal is received by the remote device and its power is measured. The transmission power of the remote transmitted signal is controlled in accordance withPower=A+(B-C)where A is representative of the desired power of the remote transmitted signal received by the base device; B is representative of the power of the base transmitted signal, transmitted by the base device; and C is representative of the measured power of the base transmitted signal as received by the remote device.

Abstract: A multiply and divide circuit having full bit level pipeline capability uses an array of bit level carry-save adders with each carry-save bit adder having a corresponding absolute value bit circuit. In one or two's complement notation, the carry-save adders subtract the binary values supplied thereto and generate an intermediate binary signal which is supplied to the absolute value circuit. The absolute value circuit determines the absolute value of the binary numbers supplied thereto. In one mode of operation, the circuit can be used to perform division. In another mode of operation, the circuit can be used to perform multiply and accumulate operation, again with bit level pipeline capability.

Abstract: In a wireless communication system between a base unit and a remote unit, the base unit transmits periodically a sync signal in a first selected time period in a selected frequency channel. The remote unit scans the frequency channels to detect the sync signal. The remote unit transmits a response signal in the selected frequency channel. The response signal is transmitted in a second selected time period different from the first selected time period. In addition, the remote unit transmits a first control signal encoded by a first code in the selected frequency channel in a third selected time period, different from the first and second selected time periods, containing a set of functional capabilities of the remote unit. The base unit receives and decodes the first control signal to derive the set of functional capabilities of the remote unit and compares it to its own set of functional capabilities to determine a common set of functional capabilities.

Abstract: A method to encode two digital data signals is disclosed. Each of the digital signals is characterized by a bit stream. An N bit block from the first signal is mapped to a unique M bit third signal where M is greater than N. Further, the number of "0's" in the M bit third signal is less than M/2. The M bit third signal is transmitted in the event a bit from the second signal is 0, whereas the complement of the M bit third signal is transmitted in the event a bit from the second signal is 1.

Abstract: In the present invention a wireless communication system is disclosed. A base unit communicates with a remote unit. The system comprises means for transmitting, using CDMA, between the base unit and the remote unit, in one of a plurality of frequencies channels selected. In one period of time, the base unit transmits and in another period of time, different from the one period, the remote unit transmits. Further, the system comprises means for changing the one frequency channel selected to another frequency channel, different from the one frequency channel, in response to interference in the one frequency channel. Thus, communication between the base unit and the remote unit is then affected over the another frequency channel.

Abstract: A method and apparatus for generating a frequency offset estimate and a timing offset estimate from a base band signal. In an important application of the invention, a modulated carrier signal is transmitted over a transmission channel and then received and demodulated to generate the base band signal. The modulated carrier signal comprises data having a transmitted symbol frequency and phase, and a carrier signal modulated by the data. The invention simultaneously generates from the base band signal a frequency offset estimate representing the difference between the transmitted and received carrier signal frequency, and a timing offset estimate representing the difference between the transmitted symbol phase and the recovered symbol phase of the base band signal. In preferred embodiments, the base band signal is a digital signal sampled at a rate which exceeds the Nyquist rate. Typically, a sampling rate of more than two samples per symbol is adequate to meet this condition.

Abstract: A method of establishing a wireless communication link between a base unit and a remote unit is disclosed. The base unit transmits periodically a sync signal in a first selected time period in a selected frequency channel. The remote unit scans for the clock signal. The remote unit transmits a first response signal encoded by a first code in the selected frequency channel in response to the detection of the clock signal. The first response signal is transmitted in a second selected time period, different from the first selected time period. The base unit transmits a first control signal which is encoded by said first code, in the selected frequency channel, in a third selected time period, which is different from the first and second selected time periods. The first control signal contains a second code to be used in the communication session between the base unit and the remote unit. The remote unit receives the first control signal in the third time period. The remote unit decodes the first control signal.

Abstract: A method of generating and accessing a database table having data stored in a unique structure and syntax is disclosed. A database access library having an access function is created. The access function of the database access library is mapped to the database table. A data object is also created. The data object has a plurality of data attributes. Each data attribute of the data object is mapped to the database table using the access function. Accessing of the data object is independent of the structure and syntax of the database table.

Abstract: In the present invention, a method of programming a task by different programmers for operation by computers is disclosed. The task is divided into a plurality of processes with each process being programmed by a different programmer. A plurality of unique objects is defined for each process. One or more phantom objects are created in a process for use by that process (calling process), wherein upon access by the calling process, the phantom object communicates with the process (called process) having the defined object associated with the phantom object. The defined object is then accessed by the called process and the result is communicated back to the phantom object to the calling process.

Abstract: In the present invention a method of re-establishing a wireless communication after a communication break is disclosed. Prior to the communication break, a base unit transmits to a remote unit a table of channels of communication to be used. The base unit also transmits a clock signal value to the remote unit. After a communication break, the remote unit continues to count the clock signals generated from a clock signal source internal thereto. The remote unit applies a function to the value of the clock signal to obtain an entry in the table. The channel of communication associated with the entry in the table is selected by the remote unit. The base unit continues to count the clock signals generated internal thereto. The base unit applies the same function as the function used by the remote unit to the value of the clock signal to obtain an entry in the table. The base unit selects the channel of communication associated with the entry in the table.

Abstract: In the present invention, a communication system is disclosed. The communication system comprises a remote computer 20 and a local computer 40, linked by communication link 12. The local computer 40 operates a conventional alphanumeric communication program 42 which receives alphanumeric data from the remote computer 20. The local computer 40 also comprises a supervisory program 56 which is Terminate and Stay Resident in memory, and which interrupts the operation of the alphanumeric communication program 42. When a particular command query is generated from the remote computer 20, the supervisory program 56 causes the local computer 40 to respond thereto, indicating the capabilities of the local computer 40 for graphical data display.

Abstract: In the present invention, a method and an apparatus for dynamically setting a discrimination threshold for the processing of an image is disclosed. The image is composed of a matrix of pixels with each pixel having a grey scale value. The pixels are arranged in a plurality of lines with each line having a plurality of pixels. The plurality of pixels are supplied to a line buffers memory. From the line buffers memory, the white peak line and the black minimum line are supplied to a peak and minimum detectors which determine the white peak value and the black minimum value associated with an edge. The white peak value and the black minimum values are stored. The stored white peak and black minimum values are supplied to a threshold calculator to which a user selectable input is also supplied. The output of a threshold calculator is a threshold level which is used by comparator. Another input to the comparator is the grey scale value of the pixel from the image.

Abstract: Two capacitive sensors are positioned on opposite sides of the sheet material, having their outputs connected additively. The output of the capacitive sensors is then supplied to a comparator to which a known reference voltage is also supplied. An adaptive circuit adaptively changes the reference voltage.