DAC/driver waveform generator with phase lock rise time control
AssigneeInternational Business Machines Corporation
InventorsHayden Clay Cranford JR., Raymond Paul Rizzo
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Abstract
A system that generates data waveforms for transmission on a communications network includes a series of sequentially over sampled and switch current sources whose timings are locked to a master delay line and replicas thereof. The master delay is configured as a ring oscillator with its frequency looked to a precise clock reference. The clock controls the rise and fall of the data waveforms thus making them immune to variations in semiconductor processes used to implement the system. 1 Inventors: Hayden C. Cranford, Jr. Raymond P. Rizzo
Claims16
A Network Interface Card (NIC) for coupling a device to a communications network including:
- a system interface section with functional circuits that process information so that said information can be received and forwarded to a system bus;
- a Medium Access Controller (MAC) storing and executing Medium Access Layer functions wherein information is being transferred or received in accordance with a predetermined protocol;
- and
- a Network Interface section including a receiver and a generator;
- said generator producing transmit waveforms wherein the rise and fall times of the transmit waveforms are dependent on clocked control of Master Delay Circuit and Replica Delay circuits implemented in said generator.
A waveform generator including:
- a delay phase lock loop generator being responsive to a reference frequency and operatively generating control signals at precisely spaced time intervals;
- at least one replica delay line receiving data signals and using said control signals to advance the data signals there-through;
- and
- a conversion circuit arrangement being responsive to convert signals outputted from said at least one replica delay line.
The waveform generator of claim 16 wherein the DACs further includes a plurality of switched current sources connected in a push-pull configuration.
Dependencies are inferred from the claim text.