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n101vtf
n101vtf

Key Features

  • Ultra high linearity, <= 50 PPM full scale @ 1 MHz range Voltage-to-Frequency (VTF) converter.
  • Measured linearity of some typical channels < 30 Hz in the mid range.
  • Four fully decoupled independent channels.
  • Undetectable crosstalk between channels.
  • Immunity to feedback from large and fast rising voltage swings in different channels.
  • Two outputs per channel.
  • 0 to 10 volt (or internal switch selectable 0 to 5 Volt) input range.
  • Four selectable gains; x1 (accurate calibrated default), x2, x5 & x10 (<= 3% accuracy).
  • Accepts positive (default) or negative (internal switch selectable) input polarities.
  • Accurate 1 MHz clock output from internal 4 MHz common clock circuit.
  • On board ultra high stability 0 to 10 V reference voltage output for calibration, (on board pad for 5 V output).
  • TTL output frequency range 0 to 1 MHz (2 MHz output is internal jumper selectable).
  • All frequency outputs, including the 1 MHz clock, can drive a 50 ohm cable.
  • Independent potentiometers for calibrating VTF & instrumentation amplifier modules on each channel.
  • Highest rated state of the art instrumentation amplifier and VTF integrated circuits.
  • Single width NIM module or stand-alone unit with own power supply.
  • 8-Bit Digital Output indicating the front panel gain selection (Can drive standard TTL logic).
  • High linearity Frequency-to-Voltage converter NIM module is under development. 
  Details

The N101VTF is a four channel ultra high linearity (<=50ppm) Voltage-to-Frequency Converter.

Input Characteristics

Input:
 Default 0 to 10 V (or 0 to 5 V internal switch selectable at the input of the VTF). There is no internal termination provided.
Nonlinearity:
 Ultra low nonlinearity, < = ± 0.001% @ gain = 1 to gain of 256 (Optional) 
Gain range:
 x1, x2, x5 & x10 (optional higher gain possible) 
Gain error:
 <= ± 0.02% (External resistor network must also be considered). 
Gain change with temp.:
 <= 5 PPM/deg C 
Noise:
 Ultra low noise, 4nV/sqrt(Hz) @ 1 kHz referred to input 
Gain bandwidth product:
 25 MHz 
Slew rate:
 5 V/µs (Typical) 
Setting time to 0.01%
 15 µs @ gain = 1 to 200 (Typical) for 20 Vstep 
Input Offset voltage:
 <= 25 µV (Nulled during calibration) 
Input offset V vs temp.:
 <= 0.25 µV/deg C 
Input polarity:
 Default is positive input referenced to ground. Negative input can be selected through an internal switch. 
Input connector:
 LEMO
Input impedance:
 109 ohm (Typical) 
Input gain:
 A front panel switch controls the voltage gain of the instrumentation amplifier. The gains can be selected from the front panel to be x1, x2, x5, or x10. The x1 gain is fully calibrated. The other gains are supplied to <= 3% accuracy by using three 1% resistors for the gain circuit for gains larger than x1. The resistors are further selected to be better than 1% accuracy. Which produces overall gain accuracy better than 1%. (Higher gain accuracies can be provided on special order.) 
Input range:
 The VTF voltage ranges are 0 to 10 V (default); 0 to -10 V; 0 to 5 V; or 0 to -5 V. The VTF maximum range limit (10 or 5 V) is set with an internal switch. The input range is the voltage range divided by the input gain setting. The default x1 range is fully calibrated before shipment. Another range can be calibrated if specially ordered. 
Protection:
 Inputs are protected through four low voltage drop clamping diodes and two high quality current limiting input FET transistors. 
Temperature:
 -25 to +85 deg C Input 


Output Characteristics

Output:
 Two independent but identical outputs per channel.
Output frequency range:
 Up to 2 MHz. (1 MHz range recommended for accurate work.)
Nonlinearity:
 Extremely low linearity error (<= ± 0.005% @ 1 MHz Full Scale, and <= ± 0.02% @ 2 MHz Full Scale) 
Gain error:
 <= ± 0.5% @ 0.5 MHz Full Scale, and <= ± 0.75% @ 2 MHz Full Scale 
Gain temperature coeff.
 <= ± 25 PPM/deg C @ 0.5 MHz range (<= ± 50 PPM/deg C @ 2 MHz range) 
Offset:
 <= ± 2 mV (Nulled during calibration) 
Offset temperature coeff:
 <= ± 25 µV/deg C 
Response time:
 One period of new output frequency + One clock period. 
Output rise & fall times:
 ~ 3 ns with or without 50 ohm termination. 
Output logic:
 TTL (Active high when there is no input to the VTF converter.) 
Output level:
 All frequency outputs including 1 MHz clock are 0 to 2.9 V with 50 ohm terminator and 0 to 5.3 V without terminator. 
Output pulse width:
 ~ 0.2 µs @ 1 MHz output. 
Output connector:
 Two LEMO connectors per channel. 
Output drive capability:
 VTF outputs can drive a 50 ohm coaxial cable. Termination is important if cables longer than 30 cm are used. 
Output frequency range:
 0 - 1 MHz (An internal jumper is provided for 0 - 2 MHz range). Output remains at 1 MHz (or 2 MHz) even if input exceeds 10 V (or 5 V) for positive and -10 V (or -5 V) for negative input ranges.
Temperature range:
 0 to 70 deg C for the VTF chip 
Power requirements:
 +24 VDC @ 70mA, -24VDC @ 60mA, +6 VDC @ 540mA 


Other Outputs

1 MHz clock output:
 High stability (<= 2 PPM Aging & <= 5 PPM Temperature) output from an internal 4 MHz clock with 50 ohm drive capability. Can be used as time base clock for accurate measurements. 
Voltage reference output:
 An ultra stable voltage reference output is supplied with an accurate calibrated dial. It has low drift <= ± 1.5 PPM/deg C, low initial error <= ± 1 mV, Output noise 6 µV p-p and both + 10 & + 5 V outputs. Provided for testing and calibration. Low output current, should only be used to supply calibration input to the VTF and a high impedance input volt meter. 
Output:
 Two independent but identical outputs per channel.
8 Bit digital output:
 An 8-Bit digital output is available, which corresponds to the gain selection of the four V-to-F channels. This can be used to drive any standard TTL logic device. The shunt resistance between the output of the NIM module and the TTL chip must be at least 150W or higher in order to properly drive the logic chip. 

 

Images

blockdiagram_thumbThe N101VTF™ back view.

 

 

mpxboard_thumbThe N101VTF™ front view.


Data

  1. Performance Graph

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