摘要:
A CMOS amplifier for optoelectronic receivers, the amplifier comprises two transimpedance amplifiers and two differential amplifier latches. One of the two transimpedance amplifiers has an input port to receive a current signal, such as, for example, a current signal from a photodetector, and provides a output voltage indicative of the received current signal. The other of the two transimpedance amplifiers may be viewed as having no input signal, so that it provides a reference voltage. The two transimpedance amplifiers are in close proximity to each other, so that power supply noise is a common mode signal in the output voltages of the two transimpedance amplifiers. The differential amplifier latches reject the common mode signal by comparing the reference voltage to the output voltage, and provide output logic voltages indicative of binary hard decisions. Two differential amplifier latches are employed, each with an evaluation phase on alternate transitions of a clock signal, so as to provide a higher throughput than if only one differential amplifier latch was employed.
摘要:
A current summing FIR filter can be implemented with multiple differential input stages and variable tail currents. The variable tail currents can be used to appropriately weight the present and previous digital input signals. The weighted outputs of the differential transistor pairs can be summed to provide a filtered output signal. The tail currents can be advantageously varied with variable current sources or by adjustment of the relative widths of the differential transistor pairs. In other embodiments, additional differential pairs can be added to adjust for systematic offset voltages caused by process-induced variations in the structure of circuit devices or to induce a desired offset.
摘要:
A device includes a bus, a first transmitter connected to the bus and configured to transmit a first signal over the bus in a first frequency band, a second transmitter connected to the bus and configured to transmit a second signal over the bus in a second frequency band at the same time that the first transmitter is transmitting the first signal, a first receiver connected to the bus and configured to receive the first signal transmitted over the bus in the first frequency band, and a second receiver connected to the bus and configured to receive the second signal transmitted over the bus in the second frequency band. The first frequency band and the second frequency band occupy different portions of the frequency spectrum.
摘要:
A circuit samples a voltage on a simultaneous bi-directional bus, and subtracts an outbound voltage to determine an inbound voltage. Sampling capacitors are variable to adjust for matching time constants. A mechanism is provided to sample error voltages over clock phase variations and sampling capacitor values.
摘要:
A system and method for encoding and receiving data is provided. The data is encoded as a pulse amplitude modulated signal such that the amplitude signals do not transition from the highest signal level to the lowest signal level and do not transition from the lowest signal level to the highest signal level. The encoding and decoding is performed in some embodiments via a lookup table, and in further embodiments is designed to minimize the step between sequential pulse amplitude modulated symbols.
摘要:
A current summing FIR filter can be implemented with multiple differential input stages and variable tail currents. The variable tail currents can be used to appropriately weight the present and previous digital input signals. The weighted outputs of the differential transistor pairs can be summed to provide a filtered output signal. The tail currents can be advantageously varied with variable current sources or by adjustment of the relative widths of the differential transistor pairs. In other embodiments, additional differential pairs can be added to adjust for systematic offset voltages caused by process-induced variations in the structure of circuit devices or to induce a desired offset.
摘要:
A global clock recovery circuit and port circuit determine and combine static phase adjustment information and dynamic phase adjustment information for multiple data signals. Static phase adjustment information is determined for each of the multiple data signals, and dynamic phase adjustment information is determined in common for the multiple data signals.
摘要:
A current summing FIR filter can be implemented with multiple differential input stages and variable tail currents. The variable tail currents can be used to appropriately weight the present and previous digital input signals. The weighted outputs of the differential transistor pairs can be summed to provide a filtered output signal. The tail currents can be advantageously varied with variable current sources or by adjustment of the relative widths of the differential transistor pairs. In other embodiments, additional differential pairs can be added to adjust for systematic offset voltages caused by process-induced variations in the structure of circuit devices or to induce a desired offset.
摘要:
A discrete-time analog filter, where a filter tap of the filter comprises a voltage-to-current converter and a current multiplier in a single stage so as to provide a current signal indicative of a weighted sampled voltage signal. The current signals are summed by one or more active cascode differential latches to provide an output logic signal indicative of the filtered output. The discrete-time analog filter finds applications in channel equalization, and is suitable for high data rates and low voltage applications. The voltage and current signals may be differential.