Technics ST-G7
¥ 73,800 (released in 1983)
Commentary
This is a quartz synthesizer tuner with the newly developed D/A fusion circuit and other technics technologies.
It is equipped with a D/A fusion circuit that has been completed by launching seven types of LSIs and ICs in Shinkai.
By integrating the digital section (signal control circuit) and analog section (linear section and signal transmission circuit), which had been independent in the past, and utilizing the power of microcomputer for signal control, basic audio characteristics are improved and stability is maintained.
The front end, IF circuit and MPX circuit are controlled by triple quartz control with quartz accuracy, and by refining the performance of traditional DC amplification, DC detection and DC demodulation, realize flat frequency characteristics and separation from the ultra-low band of 4 Hz.
A digital linear detector is used for the detector and a simple configuration of a high-precision one shot multivibrator and a current mirror constant current integration circuit provides low distortion and wide dynamic range audio signals.
It is also resistant to changes in elements and temperature, and achieves stable performance in actual use.
A high-rise pulse wave is used for stereo demodulation, and the DC peak sample-and-hold MPX circuit of Technics, which eliminates phase distortion, is mounted as an IC. In addition, a double-PLL MPX signal generation circuit, which controls the generation of the MPX signal with a quartz oscillation signal, is mounted to realize accurate and stable stereo demodulation even in environmental temperature changes.
By adopting quartz double convert IF, disturbance of group delay characteristics is eliminated, harmful even order spurious interference waves are sharply canceled, and desired signals are accurately extracted, contributing to ultra-low distortion.
Equipped with a self-calculating RF tuning circuit, the self-calculating loop operates as soon as the frequency of the desired station is detected, and the RF circuit is controlled to the optimum receiving state.
It is equipped with an auto-IF circuit. When a desired station is received, the microcomputer searches for and judges whether there is an adjacent station. If there is no adjacent station, it operates a high-selectivity normal circuit with ± 400 kHz detuning 55 dB. If there is an adjacent station, it operates a narrow-band, high-selectivity supernarrow circuit with ± 200 kHz detuning 25 dB to cut out interference from adjacent stations.
FM/AM16 station random access memory is mounted.
In addition, it is equipped with an auto memory function that allows memory operation with a single button.
Equipped with 10 db step 3-stage switching scanning level function, reception quality can be checked at channel selection.
Equipped with an automatic Midnight muting function, it automatically cuts white noise after broadcasting ends.
Using the signal strength lead-out function, the signal strength of the receiving station can be displayed in 2 dB steps.
Equipped with I/O terminal for PC connection (computer audio interface SH 8070 a is required for connection with PC)
The FM wing antenna terminal that can be automatically tuned is used as a see-through antenna.
When combined with program timer SH-4060, weekly program play including channel selection is possible.
It has a memory backup function for about one week.
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Model Rating
| Type | Quartz synthesizer FM/AM tuner |
| FM Tuner Section | |
| Receiving frequency | 76.1 mhz to 89.9 mhz |
| Practical Sensitivity (75 Ω) | 12.8dBf/1.2 μ V (IHF' 58) |
| SN50dB Sensitivity (75 Ω) | Mono : 18.1dBf/2.2 μ V (IHF' 58) Stereo : 38.1dBf/22 μ V (IHF' 58) |
| Distortion factor | mono:0.007% stereo:0.008% |
| Dynamic range | 120 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 : 25 dB (± 200 kHz) |
| Capture ratio | 1.0dB |
| Image interference ratio | 90dB(83MHz) |
| IF interference ratio | 105dB(83MHz) |
| Spurious interference ratio | 110dB(83MHz) |
| AM suppression ratio | 70dB |
| Stereo separation | 65dB(20Hz) 65dB(1kHz) 50dB(10kHz) |
| Leak Carrier (19 khz) | -70dB |
| <AM Tuner Section> | |
| Receiving frequency | 522 kHz to 1611 kHz |
| Practical sensitivity (S/N = 20 dB) | 290 μ V/m, 20 μ V |
| Selectivity | 55dB |
| Image interference ratio | 40dB |
| IF interference ratio | 60dB |
| <General> | |
| Power failure compensation | About 1 week |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 11W |
| External dimensions | Width 430x Height 97x Depth 377 mm |
| Weight | 4.1kg |