ADVANCE
CYW43570
4.2.6 Digital Demodulator and Bit Synchronizer
The digital demodulator and bit synchronizer take the low-IF received signal and perform an optimal frequency tracking and bit
synchronization algorithm.
4.2.7 Receiver Signal Strength Indicator
The radio portion of the CYW43570 provides a receiver signal strength indicator (RSSI) signal to the baseband, so that the controller
can take part in a Bluetooth power-controlled link by providing a metric of its own receiver signal strength to determine whether the
transmitter should increase or decrease its output power.
4.2.8 Local Oscillator Generation
A local oscillator (LO) generation provides fast frequency hopping (1600 hops/second) across the 79 maximum available channels.
The LO generation subblock employs an architecture for high immunity to LO pulling during PA operation. The CYW43570 uses an
internal RF and IF loop filter.
4.2.9 Calibration
The CYW43570 radio transceiver features an automated calibration scheme that is fully self contained in the radio. No user interaction
is required during normal operation or during manufacturing to provide the optimal performance. Calibration optimizes the perfor-
mance of all the major blocks within the radio to within 2% of optimal conditions, including gain and phase characteristics of filters,
matching between key components, and key gain blocks. This takes into account process variation and temperature variation.
Calibration occurs transparently during normal operation during the settling time of the hops and calibrates for temperature variations
as the device cools and heats during normal operation in its environment.
Document Number: 002-15054 Rev. *I
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