Panasonic BL-C230A

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BL-C230A
4.1.5. Sound Block
Microphone(MIC701)
Input sound.
PCM Codec (IC702)
Power Supply Voltage: 3.3 V
IC702 with built-in microphone amplifier, speaker amplifier and video amplifier is a low powered, compact, monaural codec.
A regulator to stabilize the characteristics of the codec which is sensitive to noise is equipped.
IC702 can keep the audio performance unchanged by the characteristics of the power supply circuit.
In digital signal processing, HPF, notch filter and 5 Band Equalizer are equipped for noise reduction in some bandwidth and this
makes sound effect processing more flexible.
Flow of Sound Signal
[Microphone sound]
1. The sound data input from the microphone is amplified by the amplifier in the PCM Codec (IC702) and built-in ALC. The data
is converted to the digital signal by the ADC, then the PCM data in the form of 8 KHz/8 bit is output through the Serial I/F to the
IC101 on the CPU board as the 64kbps data.
2. The PCM Codec (IC702) supplied 12MHz CLK from the host CPU (IC101), generates 8KHz and 56KHz in the built-in PLL cir-
cuit and transfers the serial data.
IC702 is controlled by CPU (IC101) using the I2C and registered.
[Speaker sound]
The PCM Codec (IC702) receives the data of the speaker sound which has been previously assigned and outputs it to the
speaker through DAC.
4.1.6. Pyroelectric Infrared Sensor Block
Pyroelectric Infrared Sensor (IC704)
Operating Power Supply: +3.1 V (+A3.1 VS)
Package: 3 pin Board Insertion Type
Changes temperature variation into analogue signal which it emits when a heat source, such as a person, comes into detection
area.
The analogue signal is amplified by Operational Amplifier (IC703).
Circuits Built-in Operational Amplifier (IC703)
Operating Power Supply: +3.1 V (+A3.1 VS)
Amplifies analogue signal from Pyroelectric Infrared Sensor (IC704).
Amplified analogue signal input the AD input terminal in CPU (IC101)
Analogue Switch (IC701)
Operating Power Supply: +3.1 V (+A3.1 VS)
Package: 8 pin SSOP
Switches the gain setting of the Operational Amplifier(IC703). The terminal status below shows each gain setting.