Front End Board

Frontend Board Used in monitors with serial number prefix ≤ 3720G. for M1353A

(M1350-66517)

Figure 6-1 Frontend Board

The Frontend board contains the analog circuitry for measuring all the possible fetal parameters of the M1353A. The FOCUS ASIC on the board provide the US timing and window control, and controls the ECG.

Each type of transducer has a specific mode resistor which is recognized by the M1353A when the transducer is connected to an input socket. In this way, different types of transducer can be used without having to recalibrate the system.

ECG The FOCUS IC divides the 4 MHz system clock to generate a 181 kHz clock. A power stage generates the power clock for the ECG transducers. The ECG signal modulates the supply current of the transducer. The modulated current is detected, amplified and bandpass filtered (1 - 250 Hz). Block DECG/MECG1 is unused.

US The US transducer transmits 998.4 kHz ultrasound bursts which are generated by the FOCUS IC. The burst widths are controlled by software. The transmitter amplifier supplies 5 Vpp at the Cardio sockets. The repetition rate is 3.2 kHz.

The received 998 kHz signal is amplified by a high frequency amplifier with a gain of 120 and then split to provide a reference path a and a compare path b. The two demodulators a and b are independently controlled by software in their receive windows by the FOCUS IC. The demodulated LF signals are bandpass filtered (100 - 500 Hz) and amplified by a software controlled gain of 180 to 1860 in eight steps. The FMP-LF path is independently demodulated, bandpass filtered and amplified by a factor of 18.

TOCO The pins of the TOCO/IUP socket are electrically isolated, connected by three transformers (excitation, sense and mode). The excitation voltage is a 2.4 kHz square wave with an amplitude of 3.5VRMS. The frequency is generated in the control chip by dividing the 4

MHz system clock.

The sense input signal is amplified by 93.75 (40∝ ;V/V/mmHg) or 750 (5∝ ;V/V/mmHg), rectified with a synchronous detector and lowpass filtered with a cutoff frequency of 7.5 Hz. All LF signals are multiplexed, sampled at either 1600 or 800 Hz, and A/D converted with 12-bit resolution.

The marker cable and the switch board are also connected to the Frontend board.

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Chapter 6 Theory of Operation

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Philips M1353A, M1351A manual M1350-66517, Frontend Board
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M1353A, M1351A specifications

Philips M1351A and M1353A are advanced medical monitoring devices designed to enhance patient care in various healthcare settings. These monitors are widely recognized for their precision, reliability, and user-friendly interface, making them essential tools for clinicians and healthcare providers.

The Philips M1351A is a compact portable monitor specifically tailored for adult, pediatric, and neonatal care. It is equipped with multiple physiological parameters, enabling healthcare professionals to track vital signs such as heart rate, respiratory rate, non-invasive blood pressure, and temperature. One of its standout features is the ability to display real-time waveforms, providing clinicians with instant access to critical patient information.

On the other hand, the Philips M1353A builds on the M1351A's robust capabilities, integrating advanced features that enhance monitoring capabilities. This model includes additional measurement modalities such as invasive blood pressure and capnography, allowing for comprehensive patient management. Its larger screen provides clear, easy-to-read data, and its intuitive interface ensures quick navigation through the various monitoring functions.

Both monitors utilize state-of-the-art technologies to ensure accurate and reliable measurements. The smart algorithm used in these devices minimizes the possibility of false readings, providing healthcare professionals with the confidence needed for effective clinical decision-making. The Philips M1351A and M1353A also feature an integrated alarm system that notifies caregivers of critical changes in patient conditions, ensuring timely interventions.

In terms of connectivity, these models facilitate seamless integration with hospital networks and electronic medical records (EMR) systems. This interoperability enhances the overall workflow in a clinical environment, allowing patient information to be shared efficiently amongst healthcare teams.

Additionally, the Philips M1351A and M1353A are designed with patient comfort in mind. They are lightweight and portable, making them suitable for diverse environments, from emergency departments to patient transport. Their rugged design ensures durability in high-paced settings, meeting the rigorous demands of modern healthcare.

In summary, the Philips M1351A and M1353A monitors serve as essential tools in contemporary medical practice, offering comprehensive monitoring capabilities, advanced technologies, and a user-centric design. These features collectively contribute to improved patient outcomes and enhanced overall healthcare delivery.
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