Abstract: A transmit portion of a WB-CDMA transceiver generates one or more spread data streams having values represented by a single bit, allowing for filtering of spread and combined data streams with a root raised cosine (RRC) filter employing single-bit multipliers. The RRC filter is a digital filter that i) employs multiplication of two values in which the length of at least one value is one bit; ii) is preferably implemented with muxs or a simple logic operator; and iii) may employ upsampling and modulation encoding of filter coefficients to reduce the coefficient length to, for example, one bit. The RRC filter may be an FIR filter having either one-bit or multi-bit coefficients, and apply RRC filtering to a spread user stream either before or after the spread user streams are combined. For some implementations, RRC filters are employed to filter each spread user stream prior to combining several processed user steams.

Abstract: A phase shifter network receives at an input node an input clock signal which does not contain higher order harmonics and generates first and second phase-shifted clock signals which are 90° apart and which have the same frequency as the input clock signal. First and second voltage comparators receive the first and second phase-shifted clock signals, respectively, and generates first and second squared clock signals, respectively, which are 90° apart and which have the same frequency as the input clock signal. A combiner combines the first and second squared clock signals to produce an output clock signal having twice the frequency of the input clock signal.

Abstract: A mixed signal integrated circuit board having decreased sensitivity of analog circuitry to digital circuitry noise is disclosed. In the mixed-signal integrated board of the present invention, a new (second) analog ground is created. This new analog ground is not limited by the manufacturing specification of connectivity to the substrate of the circuit board and is thereby free of transient noise generated by digital components on the board. In a mixed-signal integrated circuit board of the present invention, the new analog ground becomes the preferred ground and is utilized in many sensitive analog applications including voltage and current measurements. The new analog ground is easy to create as it does not involved complicated circuitry. The new analog ground may be created even after the initial circuit schematics has been created.