Adjustable Quadrature Shadow Sinusoidal Oscillator

0.5-V Nano-Power Shadow Sinusoidal Oscillator Using Bulk-Driven Multiple-Input Operational Transconductance Amplifier

“…The proposed shadow oscillators have been compared in Table 3 with previous works [ 14 , 21 , 22 , 23 ]. Both types of oscillators with amplitude stabilization based on AGC circuits [ 14 , 21 ], as well as circuit nonlinearities [ 22 , 23 ], have been selected for comparison.…”

“…The proposed shadow oscillators have been compared in Table 3 with previous works [ 14 , 21 , 22 , 23 ]. Both types of oscillators with amplitude stabilization based on AGC circuits [ 14 , 21 ], as well as circuit nonlinearities [ 22 , 23 ], have been selected for comparison. The proposed oscillator using an amplifier to vary the frequency has a simpler structure compared with [ 14 , 21 ] that use AGC circuits to control the amplitude.…”

“…The proposed oscillator using an amplifier to vary the frequency has a simpler structure compared with [ 14 , 21 ] that use AGC circuits to control the amplitude. Compared to [ 22 ], the proposed oscillator enjoys an electronic control, and compared to [ 23 ], the proposed oscillator enjoys independent control. Compared to all previous works [ 14 , 21 , 22 , 23 ], the proposed structure consumes ultra-low levels of power, rendering it suitable for extremely low-voltage and low-power applications such as biomedical systems.…”

“…Note that, thanks to the shadow principle, the frequency of oscillations and the condition of oscillations can be controlled independently, which makes such a simple solution possible (frequency tuning does not affect the nonlinear mechanism limiting the frequency of oscillations, resulting in their constant amplitude). Note that similar solutions, based on exploiting the circuit nonlinearities, were applied in some other shadow oscillators available in literature, such as [ 22 , 23 ]. However, in more demanding cases, a special AGC circuit could also be applied in the proposed oscillator.…”

“…This technique uses external amplifiers to control the condition and the frequency of oscillation without changing the internal components of the oscillator, and thus the magnitude of the core network such as integrators is not disturbed. As a result, the performances of shadow oscillators with constant output signal amplitude have been reported in [ 22 , 23 , 24 ].…”