MITSUBISHI SOUND PROCESSOR ICs
M65845AFP
DIGITAL ECHO WITH MICROPHONE MIXING CIRCUIT
(6) Digital Echo
1 Clock oscillator circuit
This IC incorporates a current control type clock oscillator circuit in it, thus providing circuit
configuration just by connecting an Rc for current control pin 32 (CLOCK CONT).
Fully internal clock supply prevents occurrence of undesired radiation without affecting
any external circuit.
The oscillator frequency fck is following.
fck = 2 MHz(Rc=51KW)
Note:
The delay time(Td) for echo is determined by the clock
frequency(fck).
DC Current
Rc
Clock
oscillator
circuit
32
Delay time=1/fckX24XN
(N=the number of memory bits = 16384
fck = 2 MHz(Rc=51KW) : Delay time=197msec
fck = 2.6MHz(Rc=39KW) : Delay time=150msec
fck = 3.9MHz(Rc=24KW) : Delay time=100msec
Clock frequency:fck
2Å@Auto mute function
The IC carries out auto mute function at the time of powering up and switching on
MIC SW in order to suppress shock noise that the digital delay may produce.
•At power up
Mute time
(400msec)
Reset Time
•At switching on MIC SW
MIC SW OFF
Mute time
(400msec)
switching on MIC SW
MITSUBISHI
ELECTRIC
( 12 / 15 )
MITSUBISHI [ Mitsubishi Group ]
