All-Pass Filter Based Linear Voltage Controlled Quadrature Oscillator

Table 2

Comparative description of recent QO designs.

Ref.	Device used	Electronic tunability	Linear tuning law	reported (Hz)	Tuning by	THD (%)
[5]	DO-CCII	No	No	2.33 M		1.17~2.82
[10]	VDIBA	Yes	No	8.5 M		2.25
[12]	CFA	No	No	909 K		—
[14]	CFA	No	No	398 K		1.42
[23]	OTA	Yes	Yes	64 K		—
[24]	VOA	No	No	160 K		—
[25]	CFOA	No	No	159 K		3.16
[26]	CDTA	Yes	No	1.73 M		3.0
[27]	CCCDBA	Yes	No	419 K		2~1.2
[28]	CCCCTA	Yes	No	1.1 M		1~2.9
[29]	OTA	Yes	No	1.59 M		1~2.2
Proposed	CFA-MMCC	Yes	Yes	~10.2 M		0.9 ~2.8