Synthesis of angle modulated ultra wideband signals based on regenerative sampling

Abstract

For efficient low power UWB communication and ranging systems, fine grained control of the UWB signal spectral properties is desirable to maximize throughput and SNR at a given power budget and spectral mask. Simple impulse radio modulation techniques like pulse amplitude, binary phase or pulse position modulation usually do not provide the same flexibility and spectral efficiency as more complex angle modulation principles. The generation of angle modulated signals, however, is usually much more complex than for impulse radio transmitters. In this paper, a novel concept for the synthesis of pulsed angle modulated ultra wideband signals based on regenerative sampling is introduced that overcomes the above mentioned contradiction. The concept allows for generating arbitrarily phase modulated pulsed UWB signals with a low-complexity hardware. It is based on a switched injection locked oscillator that samples the phase from a high order harmonic of a phase modulated baseband signal. The signal synthesizer does not require any linear amplifiers or PLLs at RF frequency. This principle brings complex angle modulation to ultra wideband signals while at the same time retaining the feasibility of low power implementation. In this paper, this completely novel signal generation principle is introduced for the first time and its capability is theoretically and experimentally verified.

Concepts and Components for Pulsed Angle Modulated Ultra Wideband Communication and Radar Systems

“…(20) different from the injection frequency) using a varactor diode, the sinc shape of the spectrum moves on the frequency axis while the peak positions do not change. These results prove most of the main claims of the generalized sampling theory according to (5) [4].…”

“…In [3,4,19], the SILO's phase sampling principle and its applications have been investigated thoroughly. The most important results will be summarized and discussed in the following.…”

“…This expression still suggests an oscillation with ω osc -the presence of the injection signal regeneration feature that includes the frequency is not obvious. According to [4], the Fourier transform F {•} of (4) leads to:…”

“…For the synthesis of communication signals [4], any phase modulated constant envelope signal that is bandwidth limited to half pulse repetition frequency can be chosen. The maximum possible symbol rate leads to one symbol per pulse.…”

Concept for a novel low-complexity QAM transceiver architecture suitable for operation close to transition frequency

“…During startup, the weak signal of the current symbol, which is injected into the feedback loop of the oscillator, provides an initial condition for the amplitude and phase of the emerging oscillation. It is known that the phase of the injected signal can be regenerated even if injection and oscillation frequency differ significantly, i.e., by more than is required for classical frequency locking, so that the PLL circuit can be omitted [3]. This is due to the fact that the oscillator is only sensitive to the input signal for a short period during startup (thus "regenerative sampling").…”