|250,000yen(around the 1991 time)
It is a reference AV preamplifier of composition of having become independent
about the image part and the voice part.
DA-P7000, AV separate structure which dedicated the circuit of a video selector
part and an audio part to another case, respectively is adopted. This has
eliminated interference of a noise etc.
The control signal is supplied to
the video part through the power-source line and photo-coupler of video system
independent winding wire transformer adoption from the audio part. From this
signal line, it has become [ that the signal for controlling necessary minimum
current and video selector is sent, and ], and the perfect isolation of an audio
part and a video part is realized.
The discrete composition which used
the broadband high frequency transistor is adopted as a video amplifier part.
Use and the interval of the switch only for video have realized a 20MHz
Bipolar switch IC only for video is adopted as all the
selector circuits. Since a bipolar switch consists of emitter followers in which
a switch part has a low Output load impedance and the broadband characteristic,
the good switch engine performance is obtained to a video signal.
order to prevent Y signal and C signal carrying out a mutual intervention, only
Y signal selector part of the signal-processing circuit was constituted from an
another board, and the solid board structure of uprighting this on C signal
selector board so that it may become the shortest wiring distance is adopted.
It has been arranged by the curtate distance by this, without Y signal and C
signal crossing, and improvement in many characteristics is realized.
Y/C separation circuit expert DCF is carried.
calculates the perpendicular and horizontal non-correlating energy of a picture
signal per pixel, and develops and IC-izes the original algorithm which chooses
three kinds of optimal filters (BPF). When it is not a level band pass filter
(one dimension), either, when horizontal correlation is strong, and correlation
is perpendicularly strong and it is not a perpendicular band pass filter (two
dimensions) and which, either, Y/C separation is carried out with a slanting
band pass filter (one-dimensional two-dimensional +).
This is reducing level
and perpendicular dot disturbance and color Darre sharply compared with the
The same positive/negative 2 power-source
composition as an audio circuit is adopted as a video circuit. By separating a
power supply circuit and a grand circuit, inflow of the unnecessary circuit
current to a grand circuit was reduced sharply, and high S/N-ization is
Furthermore, by having adopted this composition, the coupling capacitor of an input and an output could be removed and high definition-ization is realized.
speech signal processing is adopted as an audio part. For this reason, it is
processed with a digital signal until digital conversion is carried out, analog
conversion is finally carried out and it also once outputs the signal inputted
analogically by an A/D converter.
newly developed variable current - which pulled out the original merit
of 1-bit type in the D/A conversion part -- discrete -- 1 bit of DAC are
In this DA converter, the constant current type PWM system which loses
the power-supply-voltage change itself is adopted by carrying out the constant
current drive of the electronic switch so that a circuit may not be influenced
by power source variation, and also fixed-izing the load current of a power
source. Moreover, the coupling capacitor is banished, having used the op
amplifier for audios excellent in power-source-variation exclusion capability
(made by U.S. PMI) for differential amplifier, or current / voltage conversion
circuit, and having applied direct-current servo. This eliminates AM abnormal-conditions
distortion and the merit of the linearity is pulled out to the maximum
volume is adopted as a volume circuit.
This volume can be made to carry out
variable [ of the current value of the current generator of a differential
switch ] in a volume controlling circuit, and has the structure where the rotary
encoder interlocked with the volume knob detects rotation of a knob. Thereby,
bit omission does not occur in any volume values from 0dB to -72dB.
In order to remove a Jitter and to prevent degradation of sound quality,
the Jitter free digital sound collector is employed as a Jitter removal
This circuit has dual PLL composition which consists of two PLL circuits, 1st and 2nd. Moreover, it had the frequency accuracy and stability which are equal to crystal in 2nd PLL, and the variable width of frequency has adopted as it conventionally 3 or more times and the newly developed broadband LT oscillator which attained ±3,000 ppm or more.
It restores to a digital
input signal with the clock which 1st PLL made first, and data is written in the
memory buffer for 3 words by exclusive IC. And 2nd PLL applies a
re-synchronization to the clock of 1st PLL, and generates a highly precise clock
with few Jitters. The data written in the buffer with this clock was read, and
the Jitter is banished.
Moreover, the Jitter removal effect goes up, so that the response of 2nd
PLL is slow, in order that the oscillator in a loop may pursue a Jitter
and may make a clock with many Jitters, if a PLL circuit has a quick response.
However, if it answers not much late, it will become easy to separate from
a lock, and the problem on which sound breaks off arises. Then, the stable
lock is secured by carrying out the response of "2nd PLL" to
an automatic two-step gear, and switching "high and low" according
to a situation. Moreover, the super-low-speed response of PLL is attained.
power source of a PLL circuit, the independent shunt regulator is supplied for
every block, and generating of the Jitter by inflow of a power-source noise is
suppressed to it.
The digital audio signal with which processing of surround processing etc. was performed by DSP became the ripple which became
dirty by the noise from the transmission process, and ID interface is adopted in
order to prevent sound quality degradation occurring.
ID interface has the structure of transmitting only the information whether
it is the high or low includeded in the signal instead of the digital signal
itself. This is constituted by two C-MOS FET analog switches, and when
one of the two is ON, it is already connected to the power source at one
of the two in the ground. These power sources and a ground are maintaining
the clean state with few noises. If a digital audio signal is not inputted
into a D/A converter as it is here but it is made to act as a switching
signal of two analog switches, at the time of a high signal, the switch
of a grand side will be controlled for the switch of a power-source side
by ON, respectively at the time of a low signal. Although the Hy Law relation
of the digital signal newly made by this supports the incoming signal,
the uncorrelated noise of the digital audio signal was shut out and has
realized clean D/A conversion.
As surround mode, MHT logic and
mono-logic other than the Dolby prologic are supported.
MHT logic is in
original surround mode of Mitsubishi which was encoded by Dolby surround and
which corresponds soft. The bit lack accompanying [ full digital processing is
carried out and ] it by DSP corresponds by carrying out all the channel noise
shaping, and the acoustic field effect has realized the high-definition surround
The center mode can choose REAL mode and VIRTUAL mode.
REAL mode is the mode
set up when using a center speaker, and outputs all the zones from low-pass to a
high region to a center speaker. Moreover, VIRTUAL mode is the mode set up when
not using a center speaker, and orientates words etc. in the center by the
speaker of two LR(s) by a directivity emphasis circuit.
Furthermore, it is
possible to improve the center normal position by adjusting the attainment time
of the signal of a center channel by C(CENTER) PRESENCE function.
In a MULTI DELAY function, the surround acoustic field same with having
arranged 6-12 rear speakers in the large room can be obtained using 2-4
rear speakers. The width of an acoustic field can be adjusted by switching
The DELAY time
of a rear speaker can be adjusted in REAR DELAY.
Moreover, in REAR FILTER,
the barrier property of the low pass filter which cuts the upper register of a
rear channel signal can be adjusted. It is usually set as 7kHz, and 4kHz is used
to expand a feeling of an acoustic field for using 9kHz at a mild feeling of an
In THEATER LPF, the sauce which emphasized upper
register to the movie theater play, and was recorded on it can be adjusted.
In an AZIMUTH function, when the angle (azimuth) of the playback head
has shifted to the recording head in the soft work process, gap of a soft
azimuth can be adjusted.
In an AUTO INPUT function, the state where a voice like the words which
can be heard from a center can be leaked and heard from speakers other
than a center channel is improved.
The subWoofer output
is carried. The change of the three-stage of 40Hz in all/63 Hz/80 Hz is possible
in the characteristic by digital processing in a low pass filter. The barrier
property serves as 24 dB/oct.
In mono-logic mode, a feeling of surround
is added to the video software and LD software of monophonic recording, and it
The ounce clean function in which adjustment of surround audio
mode, dubbing processing, etc. can be performed while checking on a screen is
The display is three kinds of the sub screen which opts for the
volume of each [ a main screen and ] speaker and ON/OFF of a subWoofer which can
choose the sauce of input and output, the kind of surround, etc., and the REC
monitoring screen which checks the state of recording and recording.
display of a up to [ the blue back black back besides a superimposition ] is
The Ambi Sonique surround system in which the UK Nimbus has a license is carried.
Even if it reproduces usual stereo sauce, a feeling of surround is obtained, but this surround system will demonstrate an effect,
especially if the software encoded by the Ambi Sonique system is reproduced by
A push on a button will attach the wireless remote
control which carries the writing function in which a display shines.
the auto function function in which even a button comes out and a series
of operations of the system which consisted of AV equipment corresponding
to an auto function can be performed with Mitsubishi products is carried
in this remote control. Moreover, the function of other AV equipment of
remote control is learned, and the learning function which can be operated
is also carried.
||Multichannel control amplifier
||Optical: Five lines
Coaxial: Four lines
||Optical: Two lines
Coaxial: Two lines
||Analog input: Ten lines
|Preamplifier part output
||Front 2ch, center 2ch, subWoofer 2ch, rear
|Acoustic field control (digital)
||Audio part: Width 425x height 132x depth of
Video part: Width 425x height 87x depth of 393mm
||Wireless remote control