Audio Database

The

NEC CD-830DS
99,800yen(around the 1988 time)

Description
 
The compact disk player which carries new technology, such as newly developed digital servo and an optical pickup with built-in I/V amplifier.

Newly developed 16 fs Transversal Filtering Circuit is carried.
In this circuitry, it is adding the signal which delayed the periodicity 1/2 to the signal of oversampling 8 times,Since the average interpolation system is constituted and a sampling frequency becomes twice in false, the hold aperture time was set to one half of 1.4microsec at the time of 8 time oversampling, and has obtained the smoother wave. Moreover, random noise was set to 1/root2 by addition of the data, and an S/N ratio modification of about 3dB is realized. Furthermore, the energy interpolated by a low pass filter becomes half (-6dB), the burden of a low pass filter is eased, and an expansion of a passband and a modification of phase distortion are possible.

4 DAC Balanced Summing System is adopted as a D-A-conversion part.
As for this, it is possible for you to use the digital analog converter of two pieces of Lch and Rch each, to make each other cancel the inphase noise of the digital analog converter by the side of + and -, and to make 1/root2 also reduce random noise simultaneously, and it has realized the S/N ratio modification of 3dB or more compared with the conventional scheme.
Furthermore, the glitchres digital analog converter was adopted, the sample hold circuit which newly generates a spike noise and has an ill effect on a tone quality was cut, and circuitry is made simple.

Full use of the bipolar process of a two-layer product line was made in the pickup part, and the I/V amplifier built-in optical pickup which integrated the PIN photodiode of six splitting patterns and six I/V translation amplifier of a single power-source operation on the same chip is adopted as it by reduction-izing of a chip, and shading of the IC section.
Thereby, the output of an optical pickup serves as a voltage transition type, can make an Output load impedance low, and is reducing the influence by an exogenous noise. Moreover, the error rate was reduced and the improvement in a tone quality is also realized.

In order to realize the faithful and optimal servo, the world's first digital-servo circuitry is developed and carried.
This servo circuitry is by exclusive LSImuPD6353G developed newly,It has composition which accumulated each digital loop filter of a focal servo and a tracking servo, a PWM (pulse duration modulation) output circuit, 1 track jump control circuit, the track jump counter, the brake circuitry, RF signal detection circuitry, and RF comparator on one chip.
It is building in a focal servo and a tracking servo independently,Since the arbitrary filter factors (gain, a time constant, etc.) according to a transition of the status of a pickup can be set up with the microcomputer for a system control,Unlike that to which the filter factor is being fixed like the conventional analog servo circuitry, the flexible and faithful servo is realized to a transition of the signal from a disk.
Moreover, the robustness is improved by functional concentration-ization of IC. Furthermore, the energy loss of the servo driver stage is reduced because a pickup servo serves as a PWM drive.

The griddle of 2.0mm thickness is adopted as a sole plate, and also the fine oscillation from an internal-rotation system is absorbed by adoption of a center chassis. Moreover, it has a structure strong against a visitor oscillation by sticking the sintered alloy foot (phi66.18mm) which was excellent in the vibration-proof dynamic behavior with high rigidity to a floor surface. (A selection of point shorted-to-ground / interview place is possible)

The digital stage and the analog stage are completely separated from the power transformer, and noise mixing to the analog stage is prevented.

It is possible to carry the absolute phase (signal polarity) circuit changing switch, and to put the polarity of a systemwide and the polarity of the source together.

The digital (light/coaxial) output is carried.

In order to prevent the ill effect by a digital signal, the optical-transmission scheme is adopted.

The very-thick OFC code is adopted as a power cord.

Performance time edit functions, such as a digital fadeout functionality, an auto edit function and a manual edit function, a disk change edit function, an auto space functionality, and a music window within residual time, are carried.
Moreover, a deletion special-NetWare-program play, random play, and intro scan,24 music random program memory, 3 mode repeat function between all songs / special NetWare program / A-B, a time search, a track search, an index search, 2 speed music search, a power-source on-start functionality, six kinds of time windows, etc. are possible.

The large-sized-with music calender display device in which a luminosity is changed to three steps is adopted.

The headphone jack with a volume is carried.

Wireless remote control is attached.

Attached
FourDAC basic synchronized subset sections
16fs TFC sections
I/V
LSI
A/D
Sintered
Digital

Rating of a mode
Form Compact disk player
Frequency characteristic 5Hz-20kHz±0.5dB
THD 0.0025% or less
Dynamic range 98dB or more
S/N ratio 105dB or more
Channel separation 103dB or more
Wow and flutter Below a limit-of-measurement value (quartz-crystal oscillation precision)
Output voltage 2.5Vrms
Power source AC100V, 50Hz/60Hz
Power consumption 25W
Dimensions Width 430x height 90x depth of 320mm
Width 430x height 112x depth of 328mm (maxima)
Weight 11.5kg
Adjunct Wireless remote control AR-830DS