Low Noise VCOs

Descriptions

Low phase noise, a center frequency of 80 MHz, actuation range of several 100 kHz, aaa dBm output

Prototype model

• Designed by Y. Enomoto (2018), inspired by LIGO low noise VCOs. JGW-D1808968

Noise performance

• Worse than the specification for the non-divided phase noise (klog 7425) at 1 and 10 kHz. See the table below.

• Most of the RF components are not secured to the chassis in order to allow for the quick implementation. This may cause undesired acoustic coupling.

• 

  • Frequency [Hz]	Measured Frequency noise [Hz/Hz^1/2]	Equivalent Phase noise [dBc/Hz]	ROS-102-919 specification w/o frequency division [dBc/Hz]
    0.01	5	51	--
    0.1	0.4	9	--
    1	0.1	-23	--
    10	0.05	-49	--
    100	0.05	-69	--
    1,000	0.05	-89	-98
    10,000	0.03	-113	-123
    100,000	--	--	-143

Tuning Range

• Linear range of 0.8 to 2.8 V achieved (klog 6544, klog 6638). This is smaller than the expected range of 0-5 V.

• Resulting frequency showed some kind of hops, limiting the linear range. No clear explanation exists at the moment.

• Tuning sensitivity of 0.42 MHz/V is achieved (klog 6544). This is consistent with the specification of ROS-102-919 whose sensitivity is 4.5 MHz/V typ.

• 

Endeavour model

• Sophisticated version of the prototype model.
• Things need to be evaluated before building it

Bill of Materials

• Description	Part number	Manufacture	Notes	Price/each
  Seed VCO	ROS-102-191 (with eval.board TB-10)	Minicicruits	center freq. 100 MHz
  RF amp for VCO output	LNBA-0-13-BJ-100-15	Wenzel
  RF amp for LO	LNBA-10-23-AE-100-15	Wenzel	+23 dBm output
  RF amp for the output signal	LNBDA-2-26-AC-AE-100-15	Wenzel	+26 dBm output
  Frequency divider	LNFD2-10-100-13-1-13-15	Wenzel	factor of 10
  Low noise Mixer	LNMX-X-X-X	Wenzel	no attenuation