Communication Device Clock Input Using 27 MHz System Signal
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Solution Overview
Problem
Communication devices in digital television systems rely on external crystals or specific clock inputs, which are costly and inefficient, as they do not utilize the built-in 27 MHz system clock, leading to increased material and size requirements.
Innovation Solution
A communication device capable of using a standard 27 MHz system clock input to generate internal clock frequencies, eliminating the need for external crystals and reducing costs and size by integrating the clock input into the modem's phase-locked loop and clock generation circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external crystals or specific clock inputs are used for communication devices, then the device can operate with stable clock signals, but the bill of materials cost and device size increase
Solution Approach 1:
The patent merges the communication device's clock input with the set-top box's existing 27 MHz system clock. Instead of using separate external crystals for both the set-top box and embedded communication devices, the invention allows communication devices to share the system clock resource, eliminating redundant components and reducing the bill of materials while maintaining reliable clock signal operation
Solution Approach 2:
The 27 MHz system clock is designed to serve multiple functions simultaneously - it operates as the system clock for the set-top box and as the clock input for embedded communication devices. This multi-functional approach allows a single clock source to support multiple devices, reducing the need for separate external crystals and capacitors in each communication device
2Reliability
If external crystals are used for each communication device, then each device can maintain its internal clock requirements, but the device size and material requirements increase
Solution Approach 1:
The invention combines the clocking function of communication devices with the set-top box's system clock infrastructure. By merging these separate clocking requirements into a shared resource, the physical space needed for external crystals and associated components in each communication device is eliminated, thereby reducing device size
3Reliability
If separate external crystals are used for communication devices, then each device can meet its specific clock frequency requirements, but the overall system cost increases
Solution Approach 1:
The patent merges the clocking requirements of multiple communication devices into a single shared system clock resource. This consolidation eliminates the need for separate external crystals and associated passive components in each device, significantly reducing the bill of materials and overall system manufacturing cost while maintaining reliable clock frequency operation
Solution Approach 2:
The system clock is designed with universal functionality to serve both the set-top box operations and embedded communication devices simultaneously. This multi-purpose design allows a single clock source to fulfill multiple timing requirements, reducing component count and manufacturing costs across the entire system
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces the bill of materials and costs by utilizing the existing 27 MHz system clock, enabling size savings and efficient operation within digital television systems, while supporting multiple clock frequencies through frequency detection and selection logic.
Implementation Method 1
modem device 10 includes a clock interface 15 and phase-locked loop (PLL) and clock generation circuitry (collectively 'PLL/clock generator') 20
Data Source
AI summary
According to one embodiment of the present invention, a device may receive one of multiple frequencies at a clock input of the device; determine which of the multiple frequencies is received; and generate at least one internal clock frequency for operation of the device using the received frequency. For example, such a device may be embedded within a system having a receiver to receive a satellite signal spectrum and to tune a signal channel and baseband circuitry coupled to the receiver to process digital data corresponding to the signal channel, where the baseband circuitry operates at the frequency provided to the device.