This is a sources sought notice from NIST to gather market research on the availability of digital lock-in amplifier systems for high-sensitivity phase-sensitive detection and real-time signal processing, to support electro-optic sampling and frequency-comb stabilization at the NIST Boulder site. Respondents are asked to submit information about their company, size status, and suggestions on draft specifications, as well as any standard commercial pricing or estimates. NIST anticipates that delivery, installation, and training will occur within 60 days after receipt of an order, but no specific budget amount has been provided. Responses must be submitted voluntarily and will be used to inform a potential future acquisition strategy, which may lead to a formal solicitation on SAM.gov or GSA eBuy. No obligation to award a contract is created by this notice.