Audio Database

Image of DA-F15

FM tuner using quartz PLL synthesizer system.

Quartz PLL synthesizer system is adopted, and the local oscillation frequency is controlled by 100 kHz basic signal which is 1/64 of the high precision crystal (6.4 MHz) as oscillator. By this, it can accurately tune and lock in every 100 kHz between 76 ~ 90 MHz. Moreover, the frequency system of the local oscillator realizes high precision of ± 3 kHz (-10 ~ + 60 ° C).
In this system, since the frequency is always locked to the broadcasting station frequency, optimum values for distortion characteristics and separation characteristics are always obtained.

Using a lock indicator, it is possible to check at a glance which direction the free running frequency of the local oscillator is shifted by lighting up of 3 light emitting diodes.

The selectivity of the IF stage is a switching type of Narrow and Wide, each of which is composed of two independent blocks.
Narrow selectivity consists of four 2-element ceramic filters for a high selectivity tuner, and Wide consists of a 4-pole + 6-pole phase-linear LC filter for a high S/N and low distortion tuner.

Low distortion is achieved by adopting a 4-pole + 6-pole phase linear filter.
A newly designed differential transformer and PLL MPX IC are used to improve harmonic distortion, S/N, stereo separation, and temperature stability.

The front-end section improves stability by using carefully selected dual-gate MOS FET with low noise figure, precision 5-series varicon, balanced mixer, etc.

Built-in air check oscillator (calibrator).

There were 2 types, the DA-F15 with the rack-mount carrying handle and the DA-F15S without the carrying handle.

Model Rating
Type FM stereo tuner
Practical sensitivity 1.8 μ V (10.3 dBf)
Effective selectivity (± 400 kHz) Wide:45dB
Capture ratio Wide:0.8dB
S/N ratio (stereo) Wide:77dB
Image interference ratio 110dB
IF interference ratio 110dB
Spurious interference ratio 100dB
AM suppression ratio Wide:65dB
Total harmonic distortion factor (stereo, 1 kHz) Wide:0.08%
Stereo separation
1kHz: Wide:50dB
10kHz: Wide:35dB
Carrier leak suppression ratio 65dB
Frequency characteristic 30 Hz ~ 15 kHz + 0.5 -1.0 dB
Output Level / Impedance 0 ~ 500mV/5k Ω
External dimensions DA-F15 : Width 480x Height 108x Depth 356 mm
DA-F15S : Width 424x Height 108x Depth 345 mm
Weight DA-F15:6.8kg