LM4844 Stereo 1.2W Audio Sub-System With 3D Enhancement

The LMC568 is an amplitude-linear phase-locked loop that includes a linear voltage-controlled oscillator (VCO), fully balanced phase detectors, and a carrier detect output. It utilizes LMCMOS technology to achieve high performance while maintaining low power consumption. The VCO features a linearized control range of 30%, enabling the demodulation of frequency modulation (FM) and frequency shift keying (FSK) signals. Carrier detection occurs when the phase-locked loop is synchronized to an input signal exceeding 26 mVrms. Applications of the LMC568 encompass FM subcarrier audio (SCA) and television second audio program (SAP) decoders, FSK data demodulators, and voice pagers.

The LMC568 is designed to provide robust performance in a variety of communication applications by leveraging its amplitude-linear phase-locked loop architecture. The linear VCO is a critical component, as it allows for precise frequency control, which is essential for accurately demodulating both FM and FSK signals. The 30% linearized control range of the VCO ensures that the device can accommodate variations in signal frequency without introducing significant distortion, thereby enhancing the fidelity of the demodulated output.

The fully balanced phase detectors within the LMC568 contribute to its high noise immunity and improved signal integrity. These detectors are capable of processing input signals with minimal phase error, ensuring that the output remains stable even in the presence of noise. The carrier detect output serves as a vital indicator, providing a visual or electronic signal when the phase-locked loop successfully locks onto an input signal. This feature is particularly useful in applications where signal integrity is paramount, such as in communication systems that rely on precise timing and synchronization.

In practical implementations, the LMC568 finds its utility in various consumer and professional audio applications, including FM SCA for enhanced audio broadcasting and television secondary audio programming, which allows for additional audio channels to be transmitted alongside the main program. The device also plays a significant role in FSK data demodulation, a common technique used in digital communication systems for transmitting data over radio frequencies. Furthermore, voice paging systems benefit from the LMC568's ability to maintain a stable lock on incoming signals, ensuring reliable message delivery.

Overall, the LMC568 is a versatile component well-suited for modern communication systems, offering a combination of low power consumption, high performance, and reliable operation across a range of applications. Its design reflects the advancements in LMCMOS technology, making it an ideal choice for engineers seeking efficient solutions in signal processing and demodulation tasks.The LMC568 is an amplitude-linear phase-locked loop consisting of a linear VCO fully balanced phase detectors, and a Carrier detect output. LMCMOS technology is employed for high performance with low power consumption. The VCO has a linearized control range of 30% to allow demodulation of FM and FSK signals. Carrier detect is indicated when the P LL is locked to an input signal greater than 26 mVrms. LMC568 applications include FM SCA and TV second Audio program decoders, FSK data Demodulators and voice pagers. 🔗 External reference