What is it? How does it work?
The design of this unit by the ESRF is a major leap forward for voltage to frequency converter (V2F) design, it has led to two orders of magnitude improvement in resolution as well as bringing welcome updates to usability and compatibility.
The configuration of frequency output range on the V2F100 is (10, 25, 50 or 100 MHz), with selectable polarity, frequency offset (0 or 12MHz) and input voltage range (1, 2.5, 5, 10V) are altered with a simple push button interface on the front panel.This configuration of the V2F is displayed using LEDs and stored through power cycles with non-volatile memory.
In addition to the standard LEMO outputs, the V2F100 has 2-phase quadrature output and absolute digital SSI output available on the rear through a sub-D 15 connector. This enables a setting whereby both the magnitude of the voltage and the polarity is able to be output by the V2F100. SSI is usually used in motor and encoder controls, but is available on a number of instruments for beamlines.
Each V2F100 is provided with a comprehensive calibration sheet following thorough testing. Each unit has to meet exacting standards before being shipped to the customer. The following is one form of linearity chart showing that this offset unit is linear from 0 – 10 V, see below.
The following chart shows a comparison of the V2F 1MHz and the new V2F100. This test, performed at Diamond emphasises that even at the 50Mhz the test was run at, any experiment with an integration time below 0.3s suffers significantly from poor statistics from the 1MHz V2F – the 100MHz V2F100 moves this problem out by two orders of magnitude.
- Output Frequency 0 -> 10, 20, 50 or 100 MHz TTL
- Output Voltage 0 -> ±10 V or 0 -> ±5 V or 0 -> ±2.5 V or 0 -> ±1 V
- Input Configuration Isolated BNC
- TTL output frequency offset 0 or 12 MHz (for -ve to 0 measurements in predominantly positive data)
- Linearity Error ±10ppm at stable temperature
- >16 bit measurements of 1ms acquisition periods