# :TIMebase:RCLock

:TIMebase Scaling Commands

- :TIMebase:FINE
- :TIMebase:POSition
- :TIMebase:RCLock
- :TIMebase:REFerence
- :TIMebase:SCALe
- :TIMebase:XLEFt?
- :TIMebase:XRANge
- :TIMebase:XRIGht?

## Command Syntax

    :TIMebase:RCLock {{ON | 1} | {OFF | 0}}

## Query Syntax

    :TIMebase:RCLock?

## Description

When Infiniium is connected to an oscilloscope, this command lets you enable an external clock for the horizontal timebase system instead of the internal clock.

The oscilloscope has a 10 MHz IN SMA connector that you can use to synchronize (phase lock) the oscilloscope's horizontal timebase system to a reference clock that you provide. This input can also be used to provide a lower phase noise reference than the internal reference so that the oscilloscope's jitter measurement floor is lowered on long (≥10 ms) acquisitions.

The clock you provide must meet the following specifications:

- Input frequency lock range: 10 MHz ±20 ppm
- Amplitude, sine wave input: 630 mVpp (0 dBm) min to 3.54 Vpp (+15 dBm) max
- Amplitude, square wave input: 500 mVpp min to 2.83 Vpp max
- Input impedance: 50 Ω (typical)

Notes:

- The oscilloscope will lock to input amplitudes ranging from -5 dBm to +15 dBm (sine wave); however, the best intrinsic jitter performance is achieved between 0 dBm and +15 dBm.
- For inputs at or slightly below -5 dBm, the oscillator assembly will disconnect from the external reference input, the oscilloscope application will automatically connect to the internal reference signal, and a message will appear indicating the external reference signal amplitude is too low and the oscilloscope is now using the internal reference. To continue using the external reference, you need to increase the input amplitude above -5 dBm so the hardware will remain connected to the external reference signal.
- For inputs at or slightly above +15 dBm, the oscillator assembly will disconnect from the external reference input, the oscilloscope application will automatically connect to the internal reference signal, and a message will appear indicating the external reference signal amplitude is too high and the oscilloscope is now using the internal reference. To continue using the external reference, you need to reduce the input amplitude to +15 dBm or less so the hardware will remain connected to the external reference signal.