Variable resolution capability for multichannel filter spectrometers

Area of Science:

• Electronics
• Signal Processing
• Radio Astronomy

Background:

• Traditional spectrometers have fixed resolutions, limiting real-time measurement capabilities.
• Radio astronomy often relies on multichannel filter spectrometers with inherent resolution constraints.

Purpose of the Study:

• To introduce a new electronic instrument, the spectrum expander, for improving spectrometer resolution.
• To enable real-time, high-resolution spectral measurements.

Main Methods:

• Described the principles of a two-port digital signal-processing spectrum expander.
• Formulated design rules and analyzed noise and quantization effects.
• Presented performance data from a prototype expander.

Main Results:

• The spectrum expander creates a frequency-expanded replica of the input spectrum (Sout(Ef) ≈ Sin(f)).
• A prototype expander processed signals up to 12.5 MHz, expanding them for a 128-channel, 32-MHz spectrometer.
• Signal degradation was minimal, with an output signal-to-noise ratio only ~0.1 dB lower than the input.

Conclusions:

• The spectrum expander effectively enhances spectrometer resolution, enabling advanced real-time measurements.
• The instrument offers a practical solution for fields like radio astronomy requiring higher spectral fidelity.