Analog-to-Digital Converters

Table of Contents☰

Key points:

Analog-to-digital converters (ADCs) are critical components for developing the next generation of advanced digital receivers.
The limitation of electronic ADCs (EADCs) is that their vertical resolution is compromised at high bandwidths.
There are two possible approaches to solve this problem through Photonics.
- Radio frequency, when modulated on a spectrally rich optical pulsed source, can be stretched in the optical domain through a dispersive medium, thus converting high-frequency RF signals into effectively low-frequency signals.
- This reduces the input bandwidth requirements of the back-end ADC as many times as the stretch factor of the optical pulse.
- The other Photonic approach is to use an optical clock whose fluctuations in timing (timing jitter) is much smaller than an electronic clock; which is possible with a short pulsed laser.
- High bandwidth RF signals, when sampled with stable optical clocks, can provide a much higher effective number of bits (ENOB) compared to electronic clocks.
- It has time-stretched photonic ADC with effective bandwidth 12 times higher than EADC, which enables digitisation of signals with a much larger precision.
A newly designed prototypes in the Next-Generation Photonic Analog-to-Digital Converters (NG-PADC) project which can carry out instantaneous frequency measurement, generation and transport of Radio Frequency (RF) through optical methods.
Its effective bandwidth is 12 times higher than a corresponding EADC
This could revolutionize various sectors, enabling faster digital communication, improved satellite communication, better medical imaging, and Photonic radars.

Q1) What is Photonic radar?

Photonic radars, also known as photonic-based radar systems are advanced radar systems that utilize photonic (light-based) technologies to enhance radar performance and capabilities. Traditional radar systems use radio frequency (RF) waves for detection and ranging, while photonic radars employ optical signals to achieve similar objectives.

Source: New technology developed to transport radio frequency (RF) through optical methods could improve digital & satellite communication.