Audio Database

The

DIATONE DP-105
99,800yen(1984 release)

Description
 
It is CD player which supplied technology, such as 3 beam system laser pickup and LSI only for a servo circuit.

Three beam system laser pickup original with a Diatone is carried.
By this system, the laser light first irradiated from the semiconductor laser is divided into the light and the object for tracking servos which read a signal with a grating plate by the laser light per right and left. Although the catoptric light of each of these right and left is the same output, even when it is small there, when gap arises, a difference appears in the light and darkness of each catoptric light.
This catches a tracking error, and it is controlling so that a signal detection beam always follows each pit sequence.

The focal servo which detects optically the combined state on the photo-diode by the combination of a 収光 lens and a cylinder lens is carried.
A focus is normality if the image of laser light tied on a photo-diode is a perfect circle form in this servo circuit,It has distinguished that an ellipse form is a focal error, and the shake of the upper and lower sides of the disc which rotates by this is detected, and the pickup is controlled so that the signal detection laser light from an objective lens connects an exact terminal point on a disc.

The original tracking mechanism which uses a rotary mirror is adopted.
Furthermore, the oscillating sound at the time of a high-speed search is removed by having adopted special rubber material.

In order to acquire sufficient resolving power and aberration, what was finished with 1/2 or less working accuracy of a laser light wavelength is carried in the objective lens, and the method of carrying out high-speed movement of the objective lens by change of magnetic flux density is adopted as it to the focal error signal from a servo circuit.
Moreover, the suspension is removed in order to eliminate the vibration sound in the case of a drive.

LSI for exclusive use is developed and carried in servo circuits, such as a tracking servo, a focal servo, and a pickup sending servo.
Moreover, the one-chip microcomputer is adopted as the circuit which processes a command of sequence control.

The found the integral type D/A converter of 16-bit accuracy is carried in the D/A converter.
Moreover, the Chebychev type low pass filter with original circuit composition is adopted as the analog filter after D/A conversion.

In the signal circuit from a D/A converter to a line-out terminal, no lead is used, and also direct wearing of the output terminal is carried out at the printed circuit board, and while reducing the transfer loss of a signal, degradation of the high region characteristic and noise generating are removed.
Moreover, the optimal pattern design is carried out to the printed circuit board, and the channel separation is improved.

The direct-current regulated-power-supply circuit is established independently in the analog amplifier part, and it has prevented the noise generated from a digital system or a servo circuit having a bad influence on analog circuitry.

The random program of a maximum of 30 music, search by index display, 4 mode repeat function, etc. are carried.

LSI One-chip

Rating of a mode
Form CD player
The number of channels Two-channel stereo
Frequency response 5Hz - 20000Hz
Dynamic range 94dB or more
Channel separation 90dB or more
Distortion 0.003% or less (1kHz, 0dB)
Wow and flutter Quartz accuracy (below a measurement limit)
Power consumption 18W
Dimensions Width 424x height 79x depth of 300mm
Weight 5.3kg