Frequency hopping radio transmitter apparatus and method providing very high communication security
First Claim
Patent Images
1. A radio transmitter comprising:
- a digital tuner for generating a modulated carrier signal as a bandpass signal or at baseband;
means for generating at least one fixed local oscillator signal (FLO);
first means for mixing the modulated carrier signal with the FLO signal to generate a filtered IF signal;
an analog IF unit having at least one IF stage to which the filtered IF signal is applied and from which another IF signal is output;
a tunable local oscillator (TLO) for generating a TLO signal of selectable frequency;
second means for mixing the another IF signal with the TLO signal to generate a radio frequency (RF) signal;
means for controlling the TLO and at least the digital tuner or the FLO generating means and the IF unit to generate the RF signal with RF hopping and with digital-tuner frequency hopping and/or IF hopping; and
means for processing the RF signal for transmission.
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Abstract
A radio transmitter is structured to provide frequency hopping of transmitted leakage signals in addition to RF hopping of the RF output signal. A digital computer controls a digital tuner, a TLO, a FLO, and an IF unit to provide the RF hopping and to provide digital-tuner frequency hopping and IF hopping thereby enabling the frequency hopping of transmitted leakage digital tuner and IF signals.
54 Citations
12 Claims
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1. A radio transmitter comprising:
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a digital tuner for generating a modulated carrier signal as a bandpass signal or at baseband; means for generating at least one fixed local oscillator signal (FLO); first means for mixing the modulated carrier signal with the FLO signal to generate a filtered IF signal; an analog IF unit having at least one IF stage to which the filtered IF signal is applied and from which another IF signal is output; a tunable local oscillator (TLO) for generating a TLO signal of selectable frequency; second means for mixing the another IF signal with the TLO signal to generate a radio frequency (RF) signal; means for controlling the TLO and at least the digital tuner or the FLO generating means and the IF unit to generate the RF signal with RF hopping and with digital-tuner frequency hopping and/or IF hopping; and means for processing the RF signal for transmission. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for transmitting radio signals comprising the steps of:
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generating a modulated carrier signal as a bandpass signal or at baseband; generating at least one fixed local oscillator signal (FLO); mixing the modulated carrier signal with the FLO signal to generate a filtered IF signal; applying the filtered IF signal to an analog IF unit having at least one IF stage from which another IF signal is output; generating a TLO signal of selectable frequency; mixing the another IF signal with the TLO signal to generate a radio frequency (RF) signal; controlling the TLO generation and at least the modulated carrier signal generation or the FLO generation and the IF unit to generate the RF signal with RF hopping and with digital-tuner frequency hopping and/or IF hopping; and processing the RF signal for transmission. - View Dependent Claims (11, 12)
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Specification