ECR Title: ECR: Frequency Counter for PLL error signal	DCC No: E1200936-v1
Date: 9/17/2012
Requester: Daniel Sigg	Impacted Subsystem(s): ISC
Description of Proposed Change(s): Add frequency counter capability to the PLL error signal. Since the timing system already has a frequency counter, this request only covers an additional preamplifier in the PLL error signal. The design of the preamplifier can be found here.
Reason for Change(s): When the ALS laser frequency is far away from the fiber reference, we typically use a local spectrum analyzer to roughly adjust the NPRO temperature before trying to engage the PLL. To automate this process for day-by-day operations, we like to replace the local spectrum analyzer with a remote-readout frequency counter.
Estimated Cost: 8 units at a cost of $1.5k each, total $12k
Schedule Impact Estimate: None.
Nature of Change (check all that apply): Safety Correct Hardware Correct Documentation	Improve Hardware Improve/clarify Documentation Change Interface Change Requirement
Importance: Desirable for ease of use, maintenance, safety Desirable for improved performance, reliability Essential for performance, reliability Essential for function Essential for safety	Urgency: no urgency desirable by date/event: _Feb 2013____ Essential by date/event: ____________ Immediately (ASAP)
Impacted Hardware (select all that apply): Repair/modify. List part & SNs: ______________________ Scrap & Replace. List part & SNs:_____________________ Installed units? List IFO, part & SNs: _________________ Future units to be built	Impacted Documentation (list all dwgs, design reports, test reports, specifications, etc.): D1002803, D1001423, D1100670, E1200146
Disposition (to be completed by Systems Engineering): TRB CCB Approved Additional information required. Define: [Requester re-submits with new information with the same DCC E-number for the ECR but the next version number.] Concurrence by Project Management: (Acknowledged Electronically in DCC) Project Systems Engineer: Dennis Coyne Project Systems Scientist: Peter Fritschel