All-Pass Filter Based Linear Voltage Controlled Quadrature Oscillator

Figure 3

Measured response of ETAF and QO. (a) AP phase response: (A) = 9 V.d.c.; (B) = 6 V.d.c. (b) AP-THD (%) to 7th harmonic. (c) QO wave response tuned at 10 MHz quadrature signals at and nodes. (d) QO spectral response of 10 MHz for phase-noise evaluation. (e) QO linear-tuning response. (f) Measured tuning error of VCO.

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