QN8007B/8007LB
4 FUNCTIONAL DESCRIPTION
The QN8007 is a high performance, low power, single chip FM transmitter IC that supports worldwide FM broadcast band
operation. It has idle and standby modes for saving power. RDS/RBDS data service is also supported.
4.1 Transmit Mode
The QN8007 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 QN8007 can deliver up to 121 dBV output signal to an external antenna and/or matching network. An RF VGA
provides a 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 spectral purity.
4.2 Idle and Standby Mode
The QN8007 features low power IDLE and STANDBY modes for fast turn around and power saving. After power up,
the QN8007 will enter IDLE mode automatically. If there is no transmitting requirement in a pre-determined time period,
the QN8007 will enter STANDBY mode automatically. The auto-standby function can be enabled or disabled through
the serial control interface.
4.3 Audio Interface
The QN8007 supports both analog and digital audio interfaces providing maximum flexibility in real applications.
Analog Audio Interface
The QN8007 has a highly flexible analog audio interface. For audio input, the signal is AC coupled with a 3dB corner
frequency less than 50Hz. It has 4 different input impedances and 18dB adjustable gain range (in 1.5dB step) to optimize
the SNR and linearity. The gain setting can be controlled automatically by integrated AGC or manually set through serial
interface.
The single ended audio output level is 1V peak to peak and will be AC coupled to external audio driver.
Digital Audio Interface
With digital audio, the interface operates in slave mode and supports MSB-Justified, LSB-Justified, I2S, DSP1, and DSP2.
The three interface lines are MCK, DIN, and WS. MCK and WS can be tri-stated to allow for multiplexing.
Rev 2.09 (11/09)
Confidential A
Copyright ©2009 by Quintic Corporation
Confidential Information contained herein is covered under Non-Disclosure Agreement (NDA).
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