QN8006B/8006LB
4 FUNCTIONAL DESCRIPTION
The QN8006 is a high performance, low power, single chip FM transceiver IC that supports worldwide FM broadcast band
operation. It has transmit/receive modes for normal broadcasting/tuning as well as IDLE and standby modes for saving
power. RDS/RBDS data service is also supported in both transmit and receive modes.
4.1 Transmit Mode
The QN8006 transmitter uses a highly digitized architecture. The input left and right analog audio signals are first
adjusted by two automatic gain controlled (AGC) amplifiers, and then digitized by two high resolution ADCs into the
digital domain. If a digital audio interface is used, the analog input circuits and ADCs will be bypassed. Pre-emphasis,
soft clipping and MPX encoding are then performed. If RDS mode is enabled, the RDS signal will also be mixed with the
MPX signal and the combined output will be fed into a high performance digital FM modulator which generates FM
signal at RF carrier frequency. The FM signal is then filtered and amplified by the PA.
The QN8006 can deliver up to 121dBµVp output signal to an external antenna and/or matching network. An RF VGA
provides 42 dB of output power control range in 1.5dB steps and can be programmed through the serial control bus. Output
power control and in-band power flatness can be easily achieved by a calibration circuit. This wide range of control allows
for various antenna configurations such as loop, monopole, or meandering traces on PCB. An integrated RF bandpass filter
ensures optimal output spectal purity.
4.2 Receive Mode
The QN8006 receiver also uses a highly digitized low-IF architecture, allowing for the elimination of external components
and factory adjustments.
The received RF signal is first amplified by an integrated LNA and then quadrature down-converted to IF. An integrated IF
channel filter then rejects out-of-channel interference signals. AGC is also performed simultaneously to optimize the signal
to noise ratio as well as linearity and interference rejection. The filtered signal is digitized and further processed with a
digital FM demodulator and MPX decoder. Audio processing is then performed based on received signal quality and
channel condition. Two high-quality audio DACs are integrated on chip and will be used if an analog interface is used and
will be bypassed in case of a digital audio interface. The RDS signal will also be decoded if RDS reception is enabled.
4.3 Idle and Standby Mode
The QN8006 features low power IDLE and STANDBY modes for fast turn around and power saving. After power up,
the QN8006 will enter IDLE mode automatically. If there is no transmitting or receiving requirement in a pre-determined
time period, the QN8006 will enter STANDBY mode automatically. The auto-standby function can be enabled or
disabled through the serial control interface.
4.4 Audio Interface
The QN8006 supports both analog and digital audio interfaces in four different configurations, namely, analog
transmit/analog receive, analog transmit/digital receive, digital transmit/analog receive and digital transmit/digital receive,
thus, providing maximum flexibility in real applications.
Analog Audio Interface
The QN8006 has a highly flexible analog audio interface. In transmit mode, for audio input, the signal is AC coupled
with a 3dB corner frequency less than 50Hz. It has 4 different input impedances and 16.5 dB adjustable gain range (in
Rev 2.08 (04/10)
Copyright ©2010 by Quintic Corporation
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Confidential Information contained herein is covered under Non-Disclosure Agreement (NDA).
QUANTUM [ QUANTUM RESEARCH GROUP ]
