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There are the two analog signal output systems from the VFD (IC1501).

One output is the Y and color difference signal output (Y, CR, CB) that drive the

EVF and LCD displays.  The other is the Y signal and the pure chroma signal that

is output from pins !!61!! and !!68!! of the VFD (IC1501), and is input to the

LINE OUT amplifier (IC1402) which supplies the Y and C signal to drive the S-

terminal with the output impedance of 75 .   The Y and C signals are mixed in this

IC so that the composite video signal is output from the LINE OUT terminal.

The DCR-TRV900 has the analog signal input function.  To record the analog

input signal, connect the composite video signal from a player machine or from a

TV receiver to the LINE IN (OUT) terminal, enter the DCR-TRV900 to “VIDEO”

mode and press the two RECORD button at the same time.

The composite video input signal from the external source is input to the A/D

converter (IC1200) where the analog signal is converted to the digital Y/color

difference signals data that are sent to the HONEY (IC756).

Connection of an external microphone is detected by the MIC amplifier (IC7301)

that detects the voltage change which is generated only when an external micro-

phone is connected.  The L and R channel signal of the selected microphone take

the two paths.  One output is directly sent to the AUDIO I/O (IC2001).

The other output is sent to the VCA amplifier (IC302, IC303) that controls the

audio input level using the menu only when the MANUAL level control is se-

lected.  After the VCA amplifier, this signal takes the same as the other signal and

enters the AUDIO I/O (IC2001) where selection of either the external microphone

or the built-in stereo microphone is performed.  The selected audio signal is con-

verted from analog to digital data by IC2002.  The converted signal that is the

digital data, is mixed with the digital video signal at IC1600.

There are two sources for the playback system.  One playback source is the digital

signal data that is input through the i. LINK.  The other playback source is the

digital signal data that is obtained by playing back the signal recorded on tape.

Both the playback sources are sent to IC1600 where either one of the two play-

back sources is selected.  The selected playback source is sent to D/A converter

(IC2002) where the digital signal is converted to analog signal.

The selected signal is then sent to AUDIO I/O (IC2001) where the audio output

takes the two output paths.  One path is connected to LINE OUT connector while

the other path is connected to the HEADPHONES connector.

The digital signal data that is reproduced by video head is sent to REC/PB ampli-

fier (IC1816) where the playback signals of the respective channels are amplified,

phases are compensated, the unwanted spurious is eliminated and 0CH and 1CH

are mixed.

VFD

The drum servo consists of the speed servo loop and the phase servo loops during

recording and playback.

The drum servo consists of the speed servo loop and the phase servo loops during

recording and playback.

t

t

Record Mode

Playback Mode

REF

OBJ. SIGNAL OF REF

OBJ. SIGNAL OF REF

REF

Speed 
Servo Loop

Phase 
Servo Loop

Internal Counter

Internal Counter

DRUM FG

DRUM FG

COMP SYNC

DRUM PG

X’ tal

DRUM PG

In the actual 
circuit, data is 
the fixed value 
from ROM.

In the actual 
circuit, data is 
the fixed value 
from ROM.

D. FG : Drum Frequency Generator

The reference signal is the fixed data supplied from ROM in the mechanism and 
control 

µ

P.  The time from riseup of a D. FG to riseup of the next D. FG is measured 

and compared with the fixed data from the ROM, and the error is calculated.

Riseup of D. FG

V. SYNC

PLL

INT-V

Time from riseup
of a D. FG to riseup
of next D. FG.

Riseup of D. FG

Time from riseup
of a D. FG to riseup
of next D. FG.

PG signal which is 
one output pulse 
per one rotation 
of the drum.

PG signal which is 
one output pulse 
per one rotation 
of the drum.

NTSC : 150Hz

PAL : 150Hz

Frequency 
division

INT-V (Free-running)

NTSC : 150Hz

PAL : 150Hz

D. PG : Drum Plus Generator

REF   : Reference Signal

OBJ. SIGNAL OF REF : Comparing Signal

INT : Internal

to

to

The INT-V signal is locked 
by PLL to the vertical sync, 
separated from the composite sync.  
The INT-V is compared 
with the D. PG signal.

Output signal from crystal is frequency-
divided to generate the free-running 
INT-V.  
The INT-V signal is the reference signal 
and is compared with the D. PG signal.

Record Mode

Playback Mode

REF

OBJ. SIGNAL OF REF.

REF

OBJ. SIGNAL OF REF.

ATF

Internal Counter

CAPSTAN FG

Internal Counter

C. FG : Capstan Frequency Generator

REF : Reference Signal

OBJ. SIGNAL OF REF : Comparing Signal

CAPSTAN FG

t

t

In the actual 
circuit, data is 
the fixed value 
from ROM.

In the actual 
circuit, data is 
the fixed value 
from ROM.

Riseup of C. FG

Time from riseup
of a C. FG to riseup
of next C. FG.

Riseup of C. FG

Time from riseup
of a C. FG to riseup
of next C. FG.

to

to

Speed 
Servo Loop

The reference signal is the fixed data supplied from ROM in the mechanism and 
control 

µ

P.  The time from riseup of a C. FG to riseup of the next C. FG is measured 

and compared with the fixed data from the ROM, and the error is calculated.

Phase 
Servo Loop

DRUM

PG

ATF

ERR

IC2504

(1/2)

LPF

IC2401

MECHA

CONTROL

µ

P

M

M

CAP FG

CAP PWM

DRM PWM

IC2503

(1/2)

IC3200

(1/2)

PWM

DRIVE

CAPSTAN

FG 

AMP

IC2504

(2/2)

CAPSTAN

MOTOR

DRIVE

IC2505

(1/2)

DRUM

MOTOR

DRIVE

CAPSTAN

FG

CAPSTAN

IC2503

DRUM

FG

AMP

DRUM

PG

AMP

DRM

DRUM

FG

FROM IC1900