Pendulum Instruments · Frequency Distribution Amplifiers
DA-36
Compact point-to-point reference frequency distribution amplifier over fiber or coax, low jitter, fully analog with no PLL
The DA-36 is built for one specific situation: the reference sits at point A, the instruments that need it sit at point B, there is some distance between them, and a full distribution system would be overkill. It takes 1 fiber input and 1 coax input and delivers 1 fiber output plus 4 BNC coax outputs, for a 10 MHz sine reference. Transmission is analog with no PLL, so it adds neither the phase noise of a locked loop nor its lock time, which matters for jitter-sensitive measurements. Input amplitude is 0.2–2 Vrms. It suits point-to-point extension and small-scale distribution; a facility with a dozen remote sites should look at the FDA-301 instead.
Overview
How a distribution amplifier works inside shapes the quality of what comes out. A PLL-based design regenerates a clean clock; the benefit is a stable output even when the input degrades, the cost is the phase noise of the loop itself plus the time it needs to lock. The DA-36 takes the analog route: the input is amplified and split, never resynthesized, so the phase noise profile of the original signal is kept intact and there is no lock sequence. For a system whose upstream reference is already good, a rubidium clock or a GNSS-disciplined standard for example, that is usually the right choice; the low phase noise you paid for should not be replaced by a regenerated signal in the distribution stage. The unit is compact enough to drop into a gap in an existing rack. Because it accepts both fiber and coax, it also serves as the far end of a fiber link, turning the optical signal from a remote source into coax outputs for local equipment.
Key specifications
| Standard frequency | 10 MHz (sine) |
|---|---|
| Period-to-period jitter | Under 50 ps plus optical jitter (0 ps over 1 m of fiber, typically under 100 ps over 1 km of good fiber) |
| Inputs | 1 fiber input + 1 BNC coax input |
| Outputs | 1 fiber output + 4 BNC coax outputs |
| Input amplitude range | 0.2 – 2 Vrms |
| Input impedance | 50 Ω (nominal) |
| Maximum fiber distance | 2 km |
| Distribution method | Fully analog, no PLL or frequency recovery circuit |
| Dimensions (W × D × H) | 125 × 170 × 30 mm |
| Weight | 650 g |
| Operating temperature | 0°C – +50°C |
| Storage temperature | -40°C – +70°C |
| Safety approvals | EN60950, UL 1950, CE; EMC EN55022 |
Features
Analog, no PLL
The signal is never resynthesized, so the low phase noise of the upstream reference is kept as is, with no lock time.
Fiber and coax inputs
Works as the far end of a fiber link, converting the remote signal into coax outputs for local equipment.
1 + 4 outputs
One fiber output to carry on and 4 BNC outputs for local instruments; one unit covers small-scale distribution.
Low-jitter analog distribution
Period-to-period jitter stays under 50 ps plus optical jitter, 0 ps over 1 m of fiber and typically under 100 ps over 1 km of good fiber, so the quality of the upstream reference survives the distribution stage.
Compact
Fits into spare space in an existing rack; no separate rack slot has to be planned for distribution.
Cascadable
To cover a whole building or several sites, cascade several DA-36 units instead of buying a large distribution system on day one.
Typical applications
Calibration lab
Several instruments sharing one frequency reference
A calibration lab usually runs on one rubidium clock or GPSDO as the master. The DA-36 distributes its 10 MHz sine reference in pure analog form to the counters, signal analyzers and phase noise systems in the same room, adding no PLL jitter, so every instrument traces to the same time and frequency reference as ISO 17025 requires.
Telecom equipment manufacturing
Frequency synchronization of production test stations across floors
A telecom equipment maker has to synchronize dozens of test stations across one site. The DA-36 carries the 10 MHz reference over fiber from the central standards room to other floors and halls (up to 2 km), removing the ground loops and EMI that long coax runs bring, so every station tests against the same reference; several leading telecom manufacturers already use it this way.
Building-to-building distribution
Point-to-point frequency transfer between buildings on a campus
When a reference has to cross between buildings, ground potential differences and the risk of electromagnetic pulse rule out conventional coax. The DA-36 uses fiber as the medium, giving electrical isolation and EMP resistance, and several units can be chained into a multi-point network, which suits research campuses, defense sites and multi-building plants that need one common reference.
Options and configuration
Tick the options you need; we compile the configuration list and carry it into the quote form.
Standard equipment (included)
System configuration (how many units)
Accessories, power and service
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