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US 6,212,241 B1Granted
Digital modulated signal receiver
AssigneeNEC Corporation
InventorNorihiko Higuchi
Life of this patent
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Abstract
A radio receiver receives a 4-FSK signal through a radio system and a detector detects a four-level detected signal from the 4-FSK signal. The four-level detected signal is converted into digital form by an AD converter. The digital signal is stored onto a memory. The AD conversion is performed at intervals obtained from the four-level detected signal. A CPU performs the data processing of the received digital data when the AD conversion is not performed and does not perform it when the AD conversion is performed.
Claims21
A radio receiver for receiving an input signal, comprising:
- a detector for detecting a multi-level detected signal from the input signal;
- an AD converter for converting the multi-level detected signal to a digital signal at intervals determined based on the multi-level detected signal;
- a first controller for controlling a plurality of operations of the radio receiver, the first controller being capable of operating at both a main clock frequency and a sub clock frequency, wherein the main clock frequency is higher than the sub clock frequency, the operations including data processing of the digital signal comprising decoding the digital signal into received data, storing the received data in a memory, and processing the received data stored in the memory;
- and
- a second controller for controlling operation timing of the first controller such that the first controller alternates between operation at the main clock frequency and the sub clock frequency, with the first controller operating at the main clock frequency only within time periods during which the AD converter is not performing AD conversion of the multi-level detected signal.
2 more elements
A radio selective call receiver for receiving an input signal, comprising:
- a detector for detecting a multi-level detected signal from the input signal;
- an AD converter for converting the multi-level detected signal to a digital signal;
- a decoder for decoding the digital signal to produce received data;
- a memory for storing the received data;
- a timing controller for controlling AD conversion timing of the AD converter such that the AD conversion is performed at intervals determined based on the multi-level detected signal;
- and
- a data processor for processing data to perform a plurality of operations of the radio selective call receiver, the data processor being capable of operating at both a main clock frequency and a sub clock frequency, wherein the main clock frequency is higher than the sub clock frequency, the operations including data storing and data processing of the received data, wherein the data processor operates at the main clock frequency only within time periods during which the AD conversion is not performed, and wherein the data processor operates at the sub clock frequency outside of said time periods.
4 more elements
A timing control method in a radio receiver for receiving an input signal, comprising the steps of:
- a) detecting a multi-level detected signal from the input signal;
- b) converting the multi-level detected signal from analog to digital at intervals determined based on the multi-level detected signal to produce a digital signal;
- c) controlling a plurality of operations of the radio receiver, the operations including data processing of the digital signal to decode the digital signal into received data, store the received data in a memory, and process the received data stored in the memory;
- and
- d) controlling timing of the data processing such that the data processing is performed by a processor operating at a main clock frequency only within a time period during which analog-to-digital (AD) conversion of the step b) is not performed, and controlling timing of the data processing such that the processor operates a sub clock frequency lower than the main clock freguency while the analog-to-digital conversion is not being performed.
2 more elements
A timing control method in a radio selective call receiver for receiving an input signal, comprising the steps of:
- a) detecting a multi-level detected signal from the input signal;
- b) converting the multi-level detected signal from analog to digital to produce a digital signal;
- c) decoding the digital signal to produce received data;
- d) storing the received data onto a memory;
- e) controlling timing of analog-to-digital (AD) conversion of the step b) such that the AD conversion is performed at intervals determined based on the multi-level detected signal;
- and
- f) processing data to perform a plurality of operations of the radio selective call receiver, the operations including data storing and data processing of the received data, wherein the data processing of the received data is performed by a processor operating at a main clock frequency only within time periods during which the AD conversion is not performed, and wherein the processor operates at a lower sub clock frequency while the AD conversion is being performed.
4 more elements
Dependencies are inferred from the claim text.