TEST Result: S1500118
- Checked the power supply. All voltages look quiet and stationary.
- Checked the internal RF cables too see if there is any missing shield soldering => Looked fine
- Noticed that the RFAM detector board has +/-21V for the +/-24V lines => It seems that this is nominal according to the schematic
- Noticed that the RFAM detector sensitivity were doubled fomr the other unit.
=> This is reated to the modification (E1500353) of "Controller Board D0900761-B Change 1" (doubling the monitor output gain)
- Noticed that the transfer function of the CTRL signal on the BNC and the DAQ output.
=> This is reated to the modification (E1500353) of "Servo Board D0900847-B Change 1" (servo transfer function chage)
=> The measured transfer function did not agree with the prediction from the circuit constants in this document
=> From the observation of the servo board it was found that R69 was not 200Ohm but 66.5 Ohm (See attachment 1).
This explained the measured transfer function. The actuator TF has: P 2.36, Z 120., K -1@DC (0.020@HF)
- Similarly, the TF between the CTRL port on the unit and the CTRL port on the test rig was also modified.
- The amplitude noise in dBc (SSB) was measured at the output of 27dBm. From the test sheet, the noise level with 13dBm output was also referred. From the coherence of the MON1 and MON2, the noise level was inferred. It suggests that the floor level is better than 180dBc/Hz. However, there is a 1/f like noise below 1k and is dominating the actual noise level of the RF output. Daniel suggested that we should check nonlinear downconversion from the high frequency noise due to the noise attenuator. This will be check with the coming units.