SONY ST-S333ESG
¥ 49,800 (released in 1989)
Commentary
FM/AM tuner with improved reception performance and operability while inheriting digital tuning using a tuning dial.
Although it is a synthesizer tuner, it has a tuning dial.
It is equipped with three operation modes : manual, which has the same feeling as a conventional analog tuner, auto, which starts searching for radio waves automatically when it is turned a little to either left or right, and stops when it is found, and dial preset scan, which calls up a station stored in a preset memory.
In addition, the ST-S333ESG is equipped with an auto-preset scan mode in which preset stations are received for approximately 4 seconds in sequence by simply turning the dial slightly to either left or right.
You can turn off the display except when necessary for operation such as channel selection.
Wave Optimizer Technology includes four technologies : SST, WOIS, WODD, and WODSD.
SST (Super Sound Tracing Circuit) has a role to reduce distortion at the front end.
On the front end, there is a phenomenon called tracking error, which occurs when the center frequency of the band pass filter deviates from the reception frequency. In order to reduce this, the SST divides the frequency band from 76 MHz to 90 MHz into 32 bands, and adjusts each band point to minimize the error range.
WOIS (Wave Optimized IF System) is a system that optimizes IF waveform to achieve both high selectivity and high sound quality.
The IF (Intermediate Frequency Amplification) stage accurately amplifies the intermediate frequency of 10.7 MHz and eliminates adjacent station interference that cannot be eliminated at the front end by the IF filter. In order to improve the interference rejection capability, it is good to use a filter with a narrow bandwidth. However, if you simply narrow the bandwidth and increase the selectivity, the curve becomes more and more triangular, and even necessary components cannot pass through, causing distortion.
Therefore, WOIS has the role of converting a curve that approaches a triangle into an ideal parabola. By creating a correction curve with a double-headed curve around the center frequency and synthesizing it, an IF filter with a narrow bandwidth that draws a parabola is constructed.
The Wave Optimized Direct Detector (WODD) is a detector stage whose performance has been thoroughly reviewed.
WODDs focus on the fact that the feedback capacitance of the FET, the oscillation element in the VCO circuit, shows non-linearity at the operating frequency, which is opposite to that of the varactor diode. By superimposing the curves of the FET and the varactor diode, a linear VCO is created.
WODSD (Wave Optimized Digital Stereo Decorder) is a demodulation circuit developed to realize an excellent stereo signal.
In WODSD, a 38 kHz square wave and a square wave obtained by balanced multiplication of 38 kHz and 114 kHz are added to produce a switching signal that does not generate third harmonic waves.
Radial power supply is used for circuit construction. The power supply (rectifier circuit) is placed at the required position on the board, and each part is laid out to surround it. The ground reference point is also placed in the power supply.
As a result, we succeeded in reducing the impedance of the power supply by bringing the power supply unit closer to each other, eliminating the power supply loop and connecting each unit at the shortest distance.
By adopting a direct comparator and using a PLL IC that can directly handle the high frequency of 220 MHz, the comparison frequency is raised to 100 kHz, which is the same as the channel plan of Japanese FM stations. By this, it is sufficiently separated from the 19 kHz pilot signal and 38 kHz sub signal, and noise and beat generation are greatly reduced.
It is equipped with two antenna input terminals and can be used for stations with different transmission points.
Equipped with an RF direct mode that can bypass a high-frequency amplifier, distortion generation in a strong electric field area is greatly reduced.
A total of 30 FM/AM random preset memories are installed.
It is equipped with a program memory function that enables you to record your absence by changing the receiving station at each reservation time.
A pure circuit design is used to reduce noise by turning off the microcomputer during reception.
It comes with a wireless remote control that allows you to tune from the listening position.
Model Rating
| Type | FM/AM Tuner |
| Practical sensitivity | 0.9 μ V/10.3 dBf |
| Harmonic distortion factor (1 kHz, wide) | mono:0.004% stereo:0.0075% |
| Effective selectivity | wide:70dB(400kHz) narrow:65dB(300kHz) |
| Frequency response (1 kHz, stereo) | 15 Hz to 15 kHz + 0. 2-0. 5 dB |
| Spurious interference ratio | 120 dB or more |
| Signal-to-noise ratio | mono:100dB stereo:92dB |
| Separation (1 kHz) | wide:70dB |
| Preset memory | 30-station random, multi-process memory |
| Timer compatible program memory | 4 Programs |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 20W |
| External dimensions | Width 470x Height 96x Depth 372 mm Side Wood Removal : Width 430 mm |
| Weight | 7.0kg |
| Attachment | Wireless Remote Control RM-J300 AM loop antenna FM feeder antenna Connection code |