Teac TASCAM DA-P20 Service Manual page 57

@ Analog Playback
Output signal from the head is demodulated into 16 bits parallel signal in LSI after recorded in the
sequence of Pre-Amp > LSIB > LSIA > LSIC. The output signal of DAO ~ DA15 is changed into analog
value by D/A converter PCM55. SHI and SHR output signals from LSI-C separate the left and right time-
sharing signals through the sample/Hold circuit. The frequency of this sample/hold signal is 48KHz while
analog recording, and is 44.1KHz while playing DAT music tape. The low-pass filter of 20KHz for re-
cording is also used for playing by switching it. To make the fat frequency characteristics, the high-pass
area is lowered in the opposite way of recording, and raised alittle (dB up at 20KHz) by the rear aperture
compensating circuit. ia
Finally the signals go to the line-out and the phones jacks.
@) Digital Recording
The digital audio interface signals from the Digital-In jacks go to the LSIC, and extracts the clock pulses
in the digital signals from the PLL circuit by the LC oscillation circuited in outside of LSI. Then the signals
are converted in to the binary codes by bi-phase circuit through the demodulation circuit, and is recorded
in sequence of LSIA> LSIB > Pre-Amp ~ Head > Tape. Simultaneously the Line-out and Headphone
jacks receive signals through the D/A converter for monitoring in the same way of analog playback.
@ Digital Playback
Same as analog playback, the output signals to LSIC are demodulated into bi-phase signal from binary
code in LSIC and output from DPOO. Then the digital audio interface signals are output after the voltage
level is converted by the pulse transformer through the buffer.