FX803 Signalling Processor

The CMX469A is a single-chip CMOS LSI circuit that functions as a full-duplex modem, supporting baud rates of 1200, 2400, or 4800. The mark and space frequencies for this modem are 1200/1800 Hz, 1200/2400 Hz, and 2400/4800 Hz, respectively. The tone frequencies are phase continuous, with transitions occurring at the zero crossing point. A common crystal oscillator, with a choice of two clock frequencies (1.008 MHz or 4.032 MHz), facilitates baud rate, transmit frequencies, and synchronization for both transmission and reception. This device is produced by Consumer Microcircuits Limited.

The CMX469A modem is designed for efficient data communication in various applications, leveraging its full-duplex capabilities to enable simultaneous transmission and reception of data. The modulation techniques employed, Frequency Shift Keying (FSK) and Minimum Shift Keying (MSK), provide robust performance in noisy environments, making this modem suitable for telecommunications and data transmission applications.

The selection of mark and space frequencies allows for flexibility in communication protocols, while the phase continuity of tone frequencies ensures smooth transitions, minimizing distortion during data transmission. The use of a common crystal oscillator simplifies the design and enhances reliability, ensuring that the modem operates consistently across different baud rates.

Incorporating both transmit and receive synchronization, the CMX469A is capable of adjusting to varying signal conditions, which is crucial for maintaining data integrity in real-time communications. The device's architecture supports efficient power management, making it suitable for battery-operated devices. The available clock frequencies of 1.008 MHz and 4.032 MHz provide options for optimizing performance based on specific application requirements, allowing designers to tailor the modem’s characteristics to meet the demands of their systems.

The CMX469A represents an effective solution for integrating communication capabilities into electronic designs, facilitating the development of advanced data transmission systems. Its compact form factor and integrated design reduce the overall footprint in electronic circuits, promoting ease of integration into various devices.The CMX469A is a single-chip CMOS LSI circuit which operates as a full-duplex 1200, 2400 or 4800 baud FFSK/MSK modem. The mark and space frequencies are 1200/1800, 1200/2400 and 2400/4800 Hz respectively. Tone frequencies are phase continuous; transitions occur at the zero crossing point. A common Xtal Oscillator with a choice of two Clock frequen cies (1. 008MHz or 4. 032MHz) provides baud-rate, transmit frequencies, and Rx and Tx synchronization. By Consumer Microcircuits Limited 🔗 External reference