Traveling Pulse Wave Quantizer

Abstract

A Traveling Pulse Wave Quantization method is provided for converting a time sensitive signal to a digital value. A first stop signal is delayed by a first time delay, a first plurality of times, to create a delayed first stop signal. A clock signal is delayed by a second time delay, a first plurality of times, to create a delayed clock signal first period. Each second time delay is associated with a corresponding first time delay, and the second time delay is greater than the first time delay. When the delayed first stop signal occurs before the delayed clock signal first period, a count of the delays is stopped and converted into a digital or thermometer value. An accurate resampled value is provided regardless of the duration in delay between the first stop signal and a second stop signal that is accepted after the first stop signal.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention generally relates to electronic circuitry and, more particularly, to a Traveling Pulse Wave Quantizer.[0003]2. Description of the Related Art[0004]FIGS. 1A and 1B are, respectively, a schematic diagram of a Vernier delay line (VDL) based time-to-digital converter (TDC), and an associated timing diagram (prior art). A VDL TDC is a popular choice for applications that require fine time resolution. It is based on the use of two parallel tapped delay lines, one fed with reference (start) pulses and the other line with signal (stop) pulses. The fast delay line that is used for the signal pulses is constructed or tuned to be slightly faster than the reference slow delay line. The edge of a start (reference) pulse, occurring before the stop signal pulse edge, is used as a reference, travelling along the slow delay line. The stop signal edge arrives later and propagates along the fast delay line, eventually catch...

AI Technical Summary

Benefits of technology

[0007]Disclosed herein is a Traveling Pulse Wave Quantizer, which may also be referred to as a pipelined Vernier delay line (VDL) time-to-digital (TDC), operating at rates where the clock period (Tclk) is less than the combined delay of all the delay elements (Tdel) in the slow delay line (Tclk<Tdel). The TPWQ permits more than one pair of pulses to travel simultaneously along the delay lines without corrupting one another. Signal corruption conventionally occurs in the capturing of the thermometer coded sampler output with the system clock. This is because the code forms bit-by-bit over several start pulse periods. The TPWQ disclosed herein adds a new block called a resampler to the output of the sampler. The resampler solves two problems: it prevents metastability when the data bit changes close to capturing clock edge, and it correctly realigns the different data bits that belong to one signal sample.

Problems solved by technology

If a new stop pulse is fed in before the previous thermometer coded output is captured, the result is a corrupted digital signal.

Images