SONY ST-A4
¥ 35,800 (released in 1977)
Commentary
FM/AM tuners focusing on improving reception performance.
A newly developed front end pack is used in which the harmonic amplifier and mixer are packaged for stability.
The high-frequency amplifier uses a J-FET (JFET) to obtain high sensitivity.
The IF section uses a uniphase filter with excellent group delay characteristics.
Since this uniphase filter has two elements in one pack, it has a good thermobalance, and moreover, disturbance of group delay characteristics is suppressed. Therefore, both high selectivity and low distortion factor are achieved.
An IC is used for the IF section and discriminator (detection section) to produce a stable stereo demodulation signal.
The MPX demodulation circuit uses a PLL IC that is resistant to aging and temperature changes, and achieves high separation and low distortion factor.
Since the 19 khz pilot signal is included in the audio signal, a low-pass filter is installed to prevent interference with the recording bias signal of the tape recorder.
Equipped with a high-blend switch that eliminates high-frequency noise at the FM stereo broadcast transmission.
It is equipped with a muting switch inter-station noise.
The AM tuner uses an IC or triple tune system to improve reception performance.
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Model Rating
| Type | FM/AM Tuner |
| FM Tuner Section | |
| FM Practical Sensitivity (IHF) | 1.8 μ V |
| Signal-to-noise ratio | mono:75dB stereo:68dB |
| Capture ratio | 1.0dB |
| Selectivity (IHF) | 80dB |
| Image interference ratio | 55dB |
| IF interference ratio | 100dB |
| Spurious interference ratio | 80dB |
| Strain Rate (400 Hz) | mono:0.15% stereo:0.2% |
| Stereo separation | 47dB(1kHz) |
| <AM Tuner Section> | |
| Sensitivity (when bar antenna is used) | 200 μ V/m |
| Signal-to-noise ratio | 50dB |
| <General> | |
| Power consumption | 16W |
| External dimensions | Width 410x Height 145x Depth 325 mm |
| Weight | 5.6kg |
| Sold Separately | Rack Handle AH-4A (1 set, ¥ 2,500) |