Abstract: An Infrared Data Association (IrDA) communication range (109) (e.g., 1 meter) of an IrDA compliant portable device (201) is increased to an extended range infrared communication (ERIC) range (209) (e.g., 2 to 40 meters) by extending a transmission range over an uplink channel (207) from the portable device (201) up to a base station (202) and by extending a transmission range over the downlink channel (208) from the base station (202) down to the portable device (201).

Abstract: According to the present disclosure, an parallel formatted data signal is applied to an input (300), and the data signal is divided into a first data signal and a second data signal. The second data signal is applied to a logic delay element (606) to produce a delayed second data signal that is a delayed-in-time version of the first data signal. The first data signal is applied to a first parallel-to-serial converter (706), the delayed second signal is applied to a second parallel-to-serial converter (708), and first and second bit-serial data streams are produced. A controller (710) synchronizes an Arithmetic Logic Unit (616) to the first and second bit-serial data streams so that the ALU (616) scales and sums the first and second bit-serial data streams to produce a bit-serial, sample-rate converted, output signal.

Abstract: Delayed versions of a bit-serial input sequence are created. When the interpolation involves scaled versions of the input sequence, scaled versions of the input sequence are produced. The interpolation equations are implemented by adding the delayed versions of the input sequence and the scaled versions of the input sequence together. The sign bit of each of the equated interpolation terms are applied to a multiplexer (528), and the sign bits are sequentially produced at the multiplexer output (529). The multiplexed sign bits are sequentially latched to the output of a latch (534) to produce the bit-serial interpolation with sliced output signal.

Abstract: According to the present disclosure, aperiodic data is applied to parallel register (500). When a predetermined relationship between an aperiodic load signal and a periodic oversample clock signal occurs, the aperiodic data is latched to the output (506) of the parallel register as substantially periodic data. The substantially periodic data is loaded into a sigma-delta DAC (502) for processing. The sigma-delta DAC (502) is driven by a periodic oversample clock to produce a 1-bit oversampled, time averaged representation of the substantially periodic data.

Abstract: The digital FM receiver back end receives an analog intermediate frequency signal from a radio frequency front end (310) having a heterodyne circuit (312) and an intermediate frequency filter (314). In the receiver back end (307), a digital demodulator (330) having a hard limiter (333), a direct phase digitizer (336), and a phase differential circuit (339) produces a digital phase differential signal from the analog intermediate frequency signal. Next, a digital processor (360) filters and reduces noise in the digital phase differential signal using a bandpass filter (362), a de-emphasis filter (364), and an expandor (366). Finally, a pulse-width-modulation audio amplifier (380) prepares the signal for reproduction on an audio speaker (390). The digital FM receiver back end avoids inherent DC offset problems common to analog FM receivers, and it also offers a reduced complexity, size, and power consumption alternative to conventional digital FM receivers.

Abstract: A bit-serial digital expandor includes a bit-serial dual scaler block (340), a bit-serial rectifier block (320), a bit-serial lowpass wave digital filter block (350), a bit-serial scaler with overflow detection block (360), a bit-serial multiplier block (380), and a bit-serial scaler and clipper block (395). This bit-serial expandor can be used in an AMPS cellular telephone receiver to produce a receiver having a lower silicon area, gate count, and current drain compared to equivalent parallel architecture receivers.

Abstract: A bit-serial compressor (106) has a pre-divider circuit (208) receiving input serial data and generating a partial numerator. Divider circuit (210) divides the partial numerator by a denominator and generates a partial remainder that is fed back to the pre-divider circuit (208). Divider circuit (210) also generates serial data that is sent to an absolute value circuit (216) and then to a bit-serial filter (218). Bit-serial filter (218) generates an average signal from the serial data. A comparator circuit (224) compares the average signal to a threshold signal and generates the greater of the average signal or the threshold signal for use as a denominator in a next division cycle. The divider circuit includes an overflow control circuit (618) which detects overflow from the carryout bit of the partial remainder operation at the beginning of a division cycle and the sign bit of the numerator. If overflow is detected, the output is clipped according to whether the numerator is positive or negative.

Abstract: Bit-serial digital filters use numerous flip-flops, which must be reset to a known, all-zero state for testing and start-up purposes. A method for setting a bit-serial digital filter to an all-zero state uses non-resettable flip-flops, which eliminates the increased gate count and current drain overhead of resettable flip-flops. A bit-serial digital filter is constructed using non-resettable flip-flops such as simple non-resettable D flip-flops. When a reset signal is initiated, a reset controller (350) sends an all-zero signal to reset gates (301, 321) positioned at the input to the digital filter and in each feedback loop or unit-delay path. Meanwhile, a bit-serial controller (250) cycles through its control signals to emulate the operation of the bit-serial filter. In two word cycles, each flip-flop in the digital filter will be set to a known, all-zero state, and the all-zero signal is removed to allow normal operation of the filter.