Modulation index adjustment
AssigneeAnalog Devices Global Unlimited Company
InventorsMichael W. O'Brien, Sudarshan Onkar
Life of this patent
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Abstract
Aspects of this disclosure relate to transmitting and/or receiving a frequency-shift keying signal including a packet that includes a preamble and a payload. The preamble has a first modulation index that has a smaller magnitude than a second modulation index of the payload. This can enhance frequency correction in a receive device that receives the packet.
Claims20
A communication device with frequency-shift keying, the communication device comprising:
- a modulation circuit configured to modulate a digital input signal;
- and
- a frequency synthesizer configured to receive an output of the modulation circuit and to output a frequency-shift keying signal comprising a packet, wherein the packet comprises a preamble and an other portion;
- wherein the modulation circuit is configured to adjust modulation to cause the preamble to have a first modulation index and the other portion to have a second modulation index, and wherein the second modulation index has a greater magnitude than the first modulation index.
A method of transmitting a packet using frequency-shift keying, the method comprising:
- generating a preamble of a packet such that the preamble has a first modulation index, wherein the packet is modulated with frequency-shift keying;
- generating a payload of the packet such that the payload has a second modulation index, wherein the second modulation index has a greater magnitude than the first modulation index, wherein the first and second modulation indexes each represent a frequency modulation;
- and
- transmitting the packet.
A method of processing a frequency-shift keying signal, the method comprising:
- receiving, by a receive signal path, a frequency-shift keying signal comprising a packet that comprises a preamble and a payload, wherein the preamble has a first modulation index that has a smaller magnitude than a second modulation index of the payload, and wherein a channelization filter has a passband associated with the second modulation index;
- performing frequency correction based on an output of the channelization filter associated with the preamble that has the first modulation index, wherein the channelization filter is in the receive signal path;
- and
- subsequent to said performing frequency correction, demodulating the payload that has the second modulation index.
Dependencies are inferred from the claim text.