Sony SRP-X700P - Manual (Page 41)

41
CTRL S (Control S)
It is a Sony’s wired remote control protocol duplicating infrared control one being applied to
many consumer products. The CTRL S is one way being not available in returned data that
informs remote controller about status of each device, such as VTR, projector, etc.
DA (Digital to Analog)
Converting digital signal to analog signal
DC +48 V
It is to supply +48 V power to a condenser microphone through balanced line from, for
example, a microphone input connector of mixer.
The +48 V is applied at both ‘hot’ and ‘cold’ terminals of the input connector.
Since it is canceled at microphone, a dynamic microphone is not generally damaged even if it
receives the +48 V.
Decibel (dB)
It is a unit to express relative difference between two acoustic levels or electric signals.Wide
range of signals of power, voltage, and sound pressure level is converted to logarithmic scale.
The bel is the ratio of two quantities for the level. The decibel is 0.1 of a bel.
Power in decibel is expressed as dB=10log(P
1
/P
2
).
Voltage is re-written as dB=20log(V
1
/V
2
) since it is related to the Power ( ).
dBm
It is referenced to1 milliwatt in 600-ohm circuit.
0dBm=1mW.
In case other value in 600-ohm circuit measured, dBm=10log(P/0.001W) is applied.
Due to formula of P=ExI=E
2 /R and consumption of 0.001W in measurement across
600-ohm, 0.001=E 2 /600 is applied, therefore E=0.775V and 0dBm=0.775V.
In case other voltage value in 600-ohm circuit is measured, dBm=20log(E/0.775) is
applied.
dBu (or dBv)
It is a voltage measurement being taken with no concern for circuit impedance.
0dBu=0.775V
In case other voltage value, dBu=20log(E/0.775) is applied.
dB SPL
It is to express sound pressure level.
0dB SPL=2x10
-5 Pa (Pa ; N/m 2 ) . This is a sound level of the threshold of hearing.
60 is conversation at 3 ft (1 m).
130-140 is a sound level of the threshold of physical pain.
SPL=20log(P
1
/P
0
) is applied. (P
0
= )
dBFS
It is to express signal level in digital. ‘FS’ is abbreviation for ‘Full Scale ’.
0dBFS=digital clipping level (not distortion)
2x10 -5 N/m 2
P=ExI= E 2 /R