SONY ST-P7J
¥ 65,800 (released on November 1, 1978)
Commentary
An FM/AM tuner with a compact body of the same size as the pre-main amplifier TA-P7F of the PRECISE component and circuit technology such as a crystal lock digital frequency synthesizer receiving system.
With the Digital Frequency Synthesizer (frequency rigidity) method, which is one step further than the crystal lock method which suppresses tuning deviation due to aging or temperature change, the performance of each tuner block can always be fully demonstrated.
Step reception is available at 100 kHz for FM and 9 kHz for AM.
Both FM and AM are equipped with an auto-tuning function that automatically searches for a tuning frequency and a manual tuning function that allows you to select an arbitrary station.
The manual and auto operation buttons are independent of each other. In manual tuning, you can switch between step and quick tune.
With the 4-chip microprocessor MNOS memory IC, up to 8 FM/AM stations can be preset at random. Also, with the built-in last station memory function, it is possible to store the selected station just before the power switch is turned off and before switching FM/AM.
Built-in memory -in memory scan circuit that can be automatically recalled every approximately 3.5 seconds in the order of preset memories.
The built-in canceling function of the pilot signal realizes the MPX section with high separation and low distortion factor.
The RF amplification stage by MOS FET and the FM pure electronic tuning front end by 4-stage varicap enable stable reception even under strong field input.
We have improved both selectivity and distortion factor by using carefully selected uniphase filters and IF ICs for the IF amplifier.
A muting circuit using a reed relay allows for comfortable tuning by cutting off inter-station noise without losing sound quality.
The AM receiver is equipped with an IC and a pure electronic tuner using IF carefully selected for auto-tuning.
Equipped with a 5-step signal indicator.
Model Rating
| Type | FM/AM Tuner | ||||
| FM Tuner Section | |||||
| Receiving frequency | 76 MHz to 90 MHz | ||||
| Antenna | 300 Ω Balanced Type 75 Ω Unbalanced Type |
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| Practical sensitivity | 1.8 μ V (IHF) | ||||
| SN ratio 50 dB sensitivity | Mono : 3.5 μ V (IHF) / 16.1 dBf (new IHF) Stereo : 4.0 μ V (IHF) / 37.3 dBf (new IHF) |
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| Signal-to-noise ratio | mono:77dB stereo:72dB |
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| Capture ratio | 1.0dB | ||||
| AM suppression ratio | 60dB | ||||
| Image interference ratio | 80dB | ||||
| IF interference ratio | 100dB | ||||
| Spurious interference ratio | 100dB | ||||
| Effective selectivity | 45dB(300kHz) 85dB(400kHz) |
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| Distortion factor |
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| Stereo separation | 48dB(100Hz) 50dB(1kHz) 45dB(10kHz) |
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| Frequency characteristic | 30 Hz to 15 kHz + 0. 2-0. 5 dB | ||||
| Output Level / Impedance | 750mV/4k Ω | ||||
| <AM Tuner Section> | |||||
| Receiving frequency | 531 kHz ~ 1611 kHz (at 9 kHz step) | ||||
| Sensitivity | 250 μ V/m | ||||
| Signal-to-noise ratio | 50dB | ||||
| Image interference ratio | 35dB | ||||
| Distortion factor | 0.5% (500mV/m, 400 hz) | ||||
| Selectivity | 35dB(9kHz) | ||||
| <General> | |||||
| Semiconductor used | Transistor : 31 FET : 3 IC : 16 Diode : 51 Units |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||
| Power consumption | 14W | ||||
| External dimensions | Width 215x Height 80x Depth 330 mm | ||||
| Weight | 3.5kg | ||||