Aurex ST-420

Commentary

An FM/AM tuner focusing on stereo playback.

The front-end uses a four FM series varicon and FET, and the IF uses a three stage differential type IC and a linear phase filter with a 6-pole LC block to improve both the sensitivity and sound quality.

The MPX section uses a PLL IC that reduces performance degradation due to aging and temperature changes, improving stability.

It is equipped with calibrator for air check.
When the switch on the front panel is turned ON, a 440 Hz signal is emitted and the recording level can be adjusted.

Actually measured data sheet is included.
This data sheet describes four items : FM sensitivity, SN ratio, harmonic distortion factor, and stereo separation.

Model Rating

Type	FM/AM Tuner
Circuit system	Stereo demodulation circuit using 4 series varicon, superheterodyne, PLL-IC
FM Tuner Section
Receiving frequency	76 MHz to 90 MHz
Practical sensitivity	1.9 μ V (IHF)
Harmonic distortion factor	stereo:0.3% mono:0.2%
Signal-to-noise ratio	stereo:68dB mono:72dB
Frequency characteristic	20 Hz to 15 kHz ± 1 dB
Effective selectivity	70dB
Image interference ratio	85dB
IF interference ratio	90dB
Capture ratio	1.0dB
Spurious interference ratio	100dB
AM suppression ratio	55dB
Stereo separation	45dB(1kHz)
Rated output	Fixed : 450 mv (1 khz, 100% modulation) Variable : 0 ~ 800 mv (1 kHz, 100% modulation)
Antenna terminal	300 Ω balanced, 75 Ω unbalanced
<AM Tuner Section>
Receiving frequency	525 kHz to 1,605 kHz
Practical sensitivity	300 μ V/1m (IHF, bar antenna)
Image interference ratio	35dB
IF interference ratio	35dB
Signal-to-noise ratio	50dB
Selectivity	30dB
Antenna	Ferrite bar antenna With External Antenna Terminal
<General>
Semiconductor used	Transistor : 22 FET : 2 Diode : 19 units IC : 4
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	15W
External dimensions	Width 450x Height 148x Depth 376 mm
Weight	8.3kg