Technics ST-G90
¥ 59,800 (around 1987)
¥ 55,500 (revised in 1989)
Commentary
FM/AM tuner equipped with twin RF & IF automatic switching function.
The front end is equipped with normal and super narrow twin RF circuits to further improve the performance.
In the normal circuit, a 4-pole MOS FET is used for the RF amplifier and mixing element, and an FET buffer is also installed in the local oscillator. In the super narrow circuit, a 4-pole MOS FET and a 3-line twin varicap tuning circuit are added to form a 7-line twin varicap tuning circuit as a whole.
In the ST-G90, these two circuits are automatically switched by an 8-bit microcomputer, and the optimum reception condition is always maintained. This improves the RF intermodulation spurious response by approximately 20 dB at 1 MHz compared to the conventional one.
A twin circuit is also installed in the IF section to automatically eliminate adjacent channel interference.
This circuit automatically detects adjacent interfering waves simultaneously with tuning and switches to the super narrow band (30 dB ± 200 kHz) when interfering waves exist within ± 300 kHz, and switches to the normal band (55 dB ± 400 kHz) when interfering waves are not recognized.
Combined with the installation of twin RF circuits, reception performance in practical use has been greatly improved.
By making the FM signal intensity display independent, it is possible to display up to 86 dB in 2 dB steps.
By adopting twin quartz for quartz control of the front end and MPX circuit, stable tuning accuracy without frequency drift and high performance that is stable against environmental changes during actual use are realized.
In addition, excellent frequency characteristics have been obtained by adopting the DC configuration.
Equipped with auto-scan tuning that automatically searches for a broadcasting station.
Equipped with a quartz trek level check function.
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Model Rating
| Type | FM/AM Tuner |
| FM Tuner Section | |
| Receiving frequency | 76.1 mhz to 89.9 mhz |
| Practical Sensitivity (75 Ω) | 10.3dBf/0.9 μ V (IHF' 58) |
| S/N ratio 50 dB sensitivity (75 Ω) | Mono : 18.1dBf/2.2 μ V (IHF' 58) Stereo : 38.1dBf/2.2 μ V (IHF' 58) |
| Distortion factor | mono:0.009% stereo:0.015% |
| Dynamic range | 112 dB (1 kHz, 100% mod, 0 dB) |
| Frequency characteristic | 4 hz to 18 khz + 0. 2-0. 5 db |
| Effective selectivity | Normal : 55 dB (± 400 kHz) Super narrow : 30 dB (± 200 kHz) |
| Capsule ratio | 1.0dB |
| Image Interference Ratio (83 mhz) | 130dB |
| IF Interference Ratio (83 MHz) | 130dB |
| Spurious interference ratio (83 MHz) | 130dB |
| AM suppression ratio | 55dB |
| Stereo separation | 70dB(1kHz) 57dB(10kHz) |
| Leak Carrier (19 khz) | -70dB |
| <AM Tuner Section> | |
| Receiving frequency | 522 kHz to 1629 kHz |
| Practical Sensitivity (S/N ratio 20 db) | 20 μ V, 290 μ V/m |
| Selectivity | 50dB |
| Image interference ratio | 40dB |
| IF interference ratio | 40dB |
| <General> | |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 9.0W |
| External dimensions | Width 430x Height 93.5x Depth 282 mm |
| Weight | 3.1kg |