MICROCHIP TECHNOLOGY INC. BM64S2 Manual De Usuario
BM62/64
Preliminary
2017 Microchip Technology Inc.
DS60001403C-Page 19
3.0
TRANSCEIVER
The BM62/64 module is designed and optimized for
Bluetooth 2.4 GHz system. It contains a complete radio
frequency transmitter/receiver section. An internal syn-
thesizer generates a stable clock for synchronizing with
another device.
Bluetooth 2.4 GHz system. It contains a complete radio
frequency transmitter/receiver section. An internal syn-
thesizer generates a stable clock for synchronizing with
another device.
3.1
Transmitter
The internal power amplifier (PA) has a maximum out-
put power of +4 dBm. This is applied for Class 2 or
Class 3 radios without an external RF PA.
put power of +4 dBm. This is applied for Class 2 or
Class 3 radios without an external RF PA.
The transmitter performs the IQ conversion to minimize
the frequency drift.
the frequency drift.
3.2
Receiver
The low-noise amplifier (LNA) operates with TR-com-
bined mode for single port application. It can save a pin
on the package without having an external Tx/Rx
switch.
bined mode for single port application. It can save a pin
on the package without having an external Tx/Rx
switch.
The ADC is used to sample the input analog signal and
convert it into a digital signal for demodulator analysis.
A channel filter has been integrated into the receiver
channel before the ADC, which is used to reduce the
external component count and increase the anti-inter-
ference capability.
convert it into a digital signal for demodulator analysis.
A channel filter has been integrated into the receiver
channel before the ADC, which is used to reduce the
external component count and increase the anti-inter-
ference capability.
The image rejection filter is used to reject the image fre-
quency for low-IF architecture. This filter for low-IF
architecture is intented to reduce external Band Pass
Filter (BPF) component for a super heterodyne archi-
tecture.
quency for low-IF architecture. This filter for low-IF
architecture is intented to reduce external Band Pass
Filter (BPF) component for a super heterodyne archi-
tecture.
The Received Signal Strength Indicator (RSSI) signal
feedback to the processor is used to control the RF out-
put power to make a good trade-off for effective dis-
tance and current consumption.
feedback to the processor is used to control the RF out-
put power to make a good trade-off for effective dis-
tance and current consumption.
3.3
Synthesizer
A synthesizer generates a clock for radio transceiver
operation. There is a VCO inside with a tunable internal
LC tank that can reduce variation for components. A
crystal oscillator with an internal digital trimming circuit
provides a stable clock for the synthesizer.
operation. There is a VCO inside with a tunable internal
LC tank that can reduce variation for components. A
crystal oscillator with an internal digital trimming circuit
provides a stable clock for the synthesizer.
3.4
Modem
For Bluetooth 1.2 specification and below, 1 Mbps was
the standard data rate based on the Gaussian Fre-
quency Shift Keying (GFSK) modulation scheme. This
basic rate modem meets Basic Data Rate (BDR)
requirements of Bluetooth 2.0 with Enhanced Data
Rate (EDR) specifications.
the standard data rate based on the Gaussian Fre-
quency Shift Keying (GFSK) modulation scheme. This
basic rate modem meets Basic Data Rate (BDR)
requirements of Bluetooth 2.0 with Enhanced Data
Rate (EDR) specifications.
For Bluetooth 2.0 and above specifications, EDR has
been introduced to provide the data rates of
1/2/3 Mbps. For baseband, both BDR and EDR utilize
the same 1 MHz symbol rate and 1.6 kHz slot rate. For
been introduced to provide the data rates of
1/2/3 Mbps. For baseband, both BDR and EDR utilize
the same 1 MHz symbol rate and 1.6 kHz slot rate. For
BDR, symbol 1 represents 1-bit. However, each sym-
bol in the payload part of EDR packet represents 2/3
bits. This is achieved by using two different modula-
tions, π/4 DQPSK and 8 DPSK.
bol in the payload part of EDR packet represents 2/3
bits. This is achieved by using two different modula-
tions, π/4 DQPSK and 8 DPSK.
3.5
Adaptive Frequency Hopping
(AFH)
(AFH)
The BM62/64 module has an AFH function to avoid RF
interference. It has an algorithm to check the nearby
interference and to choose clear channel for
transceiver Bluetooth signal.
interference. It has an algorithm to check the nearby
interference and to choose clear channel for
transceiver Bluetooth signal.