Aurex ST-55
¥ 49,800 (around 1980)
Commentary
Synth-type FM/AM tuner using static LSI.
In the synthesizer method, the frequency of the local oscillator corresponding to the desired reception frequency is compared with the reference signal generated by the accurate vibration of the crystal, and is controlled by a PLL circuit to keep the frequency at an accurate level, thereby greatly improving the tuning stability and accurately maintaining the sound quality best point.
In addition, the phase comparison frequency with the local oscillator has been increased to FM25kHz and AM9kHz to eliminate beats in the audible band and improve the tuning accuracy.
The S / N ratio is improved by adopting a static method for all operation keys, frequency display, indicators, etc.
In the conventional dynamic method, a signal is constantly sent in a fixed cycle to control the signal, whereas in the static method, a signal is sent only when the frequency is changed, so the number of signals to be sent is reduced and noise generation is greatly reduced.
The front-end section is equivalent to a 4-row varicon for high selectivity, and the high-sensitivity type, which receives radio waves after being amplified by an RF amplifier, has a structure that is resistant to weak radio waves.
AM/FM each 6-station preset is available.
To set a preset, press the memo Leaky and the desired channel key after tuning in Auto / Manual.
FM auto-tuning is possible by setting the mode selector switch to AUTO.
It has an output volume.
Equipped with 5 series signal indicators.
Fluorescent display tube is used for frequency display.
Tempered glass is used in the front part like the clean drive amplifier.
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Model Rating
| Type | FM/AM Tuner |
| FM Tuner Section | |
| Receiving frequency | 76.0 mhz to 90.0 mhz |
| Sensitivity (IHF) | 10.8dBf |
| Distortion Factor (1 kHz, 100% MOD) | mono:0.08% stereo:0.12% |
| Signal-to-noise ratio (IHF, A curve) | mono:80dB stereo:74dB |
| Frequency characteristic | 20 Hz to 15 kHz ± 1.5 dB |
| Selectivity (IHF) | 60dB |
| Image interference ratio | 70dB |
| IF interference ratio | 75dB |
| Capture ratio | 1.5dB |
| Spurious interference ratio | 75dB |
| AM suppression ratio | 60dB |
| Stereo separation | 50dB(1kHz) |
| Rated output | 0 ~ 600 mV (400 Hz, 100% MOD) |
| <AM Tuner Section> | |
| Receiving frequency | 522 kHz to 1,602 kHz |
| Practical sensitivity | 280 μ V/m (SN ratio 20 dB) |
| Distortion factor | 0.7% (400 Hz, 30% MOD) |
| Image interference ratio | 35dB |
| IF interference ratio | 30dB |
| Signal-to-noise ratio | 50dB |
| <General> | |
| Semiconductor used | Transistor : 32 Diode : 27 units IC : 10 |
| Pwer | AC100V 50Hz/60Hz |
| Power consumption | 13W |
| External dimensions | Width 420x Height 78x Depth 230 mm |
| Weight | 2.6kg |
| Attachment | T-shaped antenna Connection code |