Onkyo T-488F (1993) search eBay
We don't have any first-hand information on the extremely rare T-488F, a digital tuner with Onkyo's APR system (described in the T-9090 writeup below), dual antenna inputs and RDS capability (see the T-4310R writeup below for more on RDS). In addition to Wide, Narrow and Super Narrow IF bandwidth modes, the T-488F had a circuit called DYNAS which our contributor Nick describes as "a unique filtering system that automatically tracks the bandwidth according to conditions, right down to 20 kHz." Engaging DYNAS can reportedly make audible a signal that would otherwise be swamped by a strong local 100 kHz away. Nick uses the T-4970, believed to have been sold only in Germany, which was presumably identical to the T-488F except for voltage and tuning increments.
Here's a further description of the DYNAS circuit, apparently quoted from Onkyo's own sales materials:
"The U42922B is a bipolar integrated FM-IF circuit, which is controlled by software. It performs all the functions of the DYNAS system. The device is designed for car radio and home receiver applications. DYNAS is a completely new system of FM-IF processing. It uses bandpass filters with a bandwidth down to about 20 kHz compared to 160 kHz for a conventional bandpass filter, and tracks the resonant frequency to the actual frequency. Implementation of the DYNAS system drastically enhances both of the basic, classic characteristics of radio reception: selectivity and reception sensitivity. DYNAS ensures enhancement up to levels which until now were not considered physically feasible. A complete system description can be found in "DYNAS system & its application in car radios" (Jan. 1992).
Features
In comparison to conventional FM-IF systems:
More than 26 dB better selectivity in case of directly (100 kHz) adjacent transmitters"