RF DAC Transmitter Clock Gating During Idle Data Periods
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Solution Overview
Problem
Digital transmitters using RF DACs for RF signal synthesis face significant power consumption due to the continuous toggling of high-frequency LO clock signals, despite being more power efficient than analog transmitters.
Innovation Solution
Implementing an idle data detector to disable the LO clock signal when detecting idle data in the transmit data stream, thereby conserving power by ceasing the generation of RF signals during periods of inactivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LO clock signal is continuously provided to the RF DAC for RF signal synthesis, then the transmitter can maintain readiness for immediate data transmission, but power consumption increases due to continuous clock signal toggling
Solution Approach 1:
The patent implements periodic action by enabling the LO clock signal only during active data transmission periods and disabling it during idle periods. The control circuit monitors the data input signal and activates the clock signal periodically when data is present, rather than maintaining continuous operation. This approach balances transmitter readiness with power consumption by using intermittent clock signal provision based on actual transmission needs.
2Use of energy by moving object
If the LO clock signal is disabled during idle periods to reduce power consumption, then power efficiency improves, but transmission delay increases due to clock signal reactivation time
Solution Approach 1:
The patent applies preliminary action by providing a warm-up interval before completely disabling the LO clock signal when idle data is detected. During this warm-up period, the clock signal is gradually reduced or prepared for shutdown, allowing the system to transition smoothly to a low-power state. This preliminary preparation minimizes the reactivation delay when transmission resumes by ensuring the clock signal can be quickly reenabled without significant startup latency.
3Use of energy by moving object
If the LO clock signal frequency is reduced during idle periods to conserve power, then energy consumption decreases, but signal synchronization capability deteriorates
Solution Approach 1:
The patent implements local quality by applying different operational characteristics to different parts of the signal processing chain during idle periods. Specifically, the LO clock signal is completely disabled or significantly reduced in frequency only in the RF synthesis section, while other critical sections such as data processing and control circuits maintain their normal operating frequencies. This selective frequency management allows power conservation in the RF section without compromising the synchronization capabilities of other system components.
Data Source
AI summary
An apparatus, including: a clock source configured to generate a local oscillator (LO) clock signal; a radio frequency digital-to-analog converter (RF DAC) configured to generate a radio frequency (RF) signal based on a data signal and the LO clock signal; and an idle data detector configured to: detect a stream of idle data in the data signal; and disable providing the LO clock signal to at least a portion of the RF DAC in response to detecting the stream of idle data.