Aurex ST-F15/ST-F15K
¥ 62,000 (around 1978)
Commentary
FM stereo tuner using newly developed LSI.
Two newly developed LSIs make it compact.
TC-9123P is used for the synthesizer. This LSI has 1,700 elements in one chip, and is mainly responsible for PLL synthesizer functions and functions such as auto-tuning.
TC-9124P is used for control. This LSI has 5,400 elements in one chip. It is mainly for memory function and is in charge of control. It also allows preset of 10 stations.
The front-end section uses a PLL synthesizer method, in which a local oscillator circuit using a crystal oscillator is incorporated into the PLL loop to produce an accurate oscillation frequency.
The ST-F15 uses a newly developed FET and five variable capacitor (variable capacitance diode) in the front end, and uses a newly developed IC and ceramic filter in the IF (intermediate frequency) amplification stage to improve its characteristics.
Three channel selection operations are available : auto tuning, manual tuning, and preset tuning.
Uses a push switch made of conductive rubber.
It has a display that displays the preset channel numbers, stereo indicators, and signal indicators.
A fluorescent tube is used for the reception frequency display, and the signal level is displayed in 5 stages.
It is equipped with an air check calibrator capable of outputting a 1 kHz reference signal with 50% FM modulation.
There were 2 kinds of variations, ST-F15 from walkers or rollators for the elderly Ler and ST-F15K from Black.
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Model Rating
| Type | FM stereo tuner |
| Circuit system | PLL frequency tuner |
| Receiving frequency | 76.0 mhz to 90.0 mhz |
| Practical sensitivity | 10.8dBf/0.9 μ V (75 Ω) |
| Signal-to-noise ratio | stereo:68dB mono:72dB |
| Distortion Factor (1 kHz, 100%) | stereo:0.25% mono:0.15% |
| Frequency characteristic | 30 Hz ~ 15 kHz + 0.5 -1.5 dB |
| Image interference ratio | 50dB |
| IF interference ratio | 80dB |
| Capture ratio | 1.0dB |
| Spurious interference ratio | 100dB |
| AM suppression ratio | 50dB |
| Effective selectivity | 75 dB (± 400 kHz) |
| Stereo separation factor | 45dB(1kHz) |
| Rated output | 600 mv (400 Hz, 100%) |
| Output impedance | 2k Ω |
| Semiconductor used | Transistor : 17 FET : 2 Linear ICs : 2 units Digital IC : 12 pcs Diode : 45 pcs LED : 4 pcs |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 7W |
| External dimensions | Width 257x Height 54x Depth 196 mm |
| Weight | 2.2kg |