datasheetbank_Logo
Integrated circuits, Transistor, Semiconductors Search and Datasheet PDF Download Site

LA2110 View Datasheet(PDF) - SANYO -> Panasonic

Part Name
Description
View to exact match
LA2110
SANYO
SANYO -> Panasonic SANYO
LA2110 Datasheet PDF : 6 Pages
1 2 3 4 5 6
[Theory of LA2110 Noise Canceller]
LA2110
In order to simplify the operation theory, the composite signal component is given only as a low frequency signal and a
pilot cancel signal has the same phase, same amplitude as the pilot signal in the composite signal.
Since the output voltage is the differential voltage of the plus and minus input of the subtraction circuit, it is equal to the
voltage between the memory capacitor terminals. When the gate is closed, the composite signal is applied to the plus input
terminal of the subtraction circuit, and the pilot cancel signal is applied to the minus input terminal. Thus the pilot signal
is cancelled from the output and only the low frequency signal appears. In the same way, the voltage between the memory
capacitor terminals is the differential voltage of the composite signal and the pilot cancel signal, so only the low frequency
signal appears.
When pulse noise is generated and the gate opens, the plus input and minus input signal waveforms of the subtraction
circuit become equal. This is because the input impedance of the subtraction circuit is extremely high, so the memory
capacitor is considered AC-shorted. Thus, when pulse noise is generated in the composite signal, the same pulse noise
appears in minus as well as plus input of the subtraction circuit. As a result, pulse noise does not appear in the output. The
voltage in the output has a DC level difference of plus and minus input, and that is the voltage held by the memory
capacitor. This voltage is that between the memory capacitor terminals just before the gate opens, so it is the low frequency
signal voltage just before the gate opens. Because the subtraction circuit input impedance is high, no charge/discharge
current flows in the memory capacitor while the gate is open, so the memory capacitor can hold the voltage between its
terminals.
The voltage waveforms are illustrated below.
Note : The pilot cancel signal is given as sinusoidal in this explanation, but in the actual application
circuit, pilot cancel is performed by a triangular wave.
No.855–4/6
 

Share Link: 

datasheetbank.com [ Privacy Policy ] [ Request Datasheet ] [ Contact Us ]