DIATONE DA-F630
¥ 47,000 (around 1979)
Commentary
An FM/AM tuner that can preset 8 FM/AM stations.
It uses a quartz synthesizer method. This method enables electronic tuning by changing the capacitance of a variable diode using a PLL and a microcomputer. The receiving frequency is determined based on the reference frequency (FM0.1 MHz, AM1kHz) obtained from the crystal oscillator, so there is no worry about tuning deviation.
By storing frequencies in a microcomputer, you can preset up to 8 stations in total.
Since the power supply of the memory is a condenser backup system, the memory circuit operates even if the power switch is turned off. Even if the power supply is turned off due to a power failure or absence recording, the preset state is maintained for approximately 48 hours.
You can set the preset by pressing the memory button while receiving the desired station and pressing the desired preset button while the memory indicator is lit.
Manual tuning is possible using the UP/DOWN buttons.
Each press of each button changes the received frequency in 0.1 MHz steps for FM and 1 kHz steps for AM. You can also fast-forward tune by holding down the button.
The FM detection circuit employs a new quadrature detector in which a phase coil and a detection transformer are contained in the same case.
In addition, a PLL IC is employed in the MPX circuit to achieve low distortion and high separation.
The frequency is digitally displayed by the LED.
Model Rating
Type | FM/AM Tuner |
FM Tuner Section | |
Practical sensitivity | 1.9 μ V (10.8 dBf) |
Effective selectivity | 60dB |
Capture ratio | 1.5dB |
Signal-to-noise ratio | stereo:72dB mono:75dB |
Image interference ratio | 60dB |
IF interference ratio | 80dB |
Spurious interference ratio | 80dB |
Total harmonic distortion rate (1 kHz) | stereo:0.3% mono:0.2% |
Stereo separation | 40dB(1kHz) |
Frequency characteristic | 30 Hz to 15 kHz ± 3 dB |
<AM Tuner Section> | |
Practical sensitivity | 300 μ V/m |
Signal-to-noise ratio | 50dB |
Effective selectivity | 25dB |
Image interference ratio | 40dB |
Total harmonic distortion factor | 1.0% |
<General> | |
External dimensions | Width 424x Height 140x Depth 236 mm |
Weight | 3.4kg |