USB Differential Pulse Generators

PicoSource PG900 Series USB Differential Pulse Generators

Fast-edge differential pulse generators
  • Dual Technology Fast Differential Pulse Generators
  • Differential outputs with user timing deskew
  • Low jitter external trigger I/O and integral clock source

Description

The fast-transition pulse can stimulate a transmission path, device or network with a broad spectrum signal in a single instant. Such a pulse is very useful for many of the high-speed broadband measurements that we need to make; for instance in time-domain reflectometry, semiconductor test, gigabit interconnect and port test and in radar.

Differential high-speed data in particular dominates the measurement challenge in our digital, computing, interconnect and telecommunications systems. Surprisingly, cost-effective fast-transition differential pulse generators have been very hard to find … until now!

Typical applications include:

  • TDR/TDT network and match analysis
  • Spectral and flatness measurements
  • Timing, jitter and crosstalk determinations

The PG900 Pulse Generators can partner the PicoScope 9300 20 GHz Sampling Oscilloscope in many of these applications.

A versatile, portable triggered differential USB pulse generator

portable triggered differential USB pulse generator

The PicoSource PG900 Series are low-jitter triggered differential USB pulse generators. Pulse outputs are optimized for broad spectral content (fastest transition time) to best suit spectral and time-domain transmission and reflectometry measurements. An internal clock is provided for stand-alone, self-triggered operation and trigger input and output allow the generators to source or respond to system triggers. Differential outputs ensure that the proliferation of gigabit differential interconnect and systems can all be addressed (e.g. SATA, USB3, HDMI, Ethernet).

Essential to any differential test or measurement is the ability to adjust for small but significant velocity and path length differences that are bound to exist in any measurement setup. The PG900 pulse outputs can each be adjusted (time-skewed) in 1 ps increments to deskew path differences before the measurement, or to deliberately stress a transmission path with timing skew.

Despite their small size and portability the PicoSource PG900 generators pack quite a punch, with integrated Step Recovery Diode outputs of up to 6 V pk each into 50 Ω. That’s a whopping 12 V pk differential pulse amplitude to drive lossy paths or stress system ports. Outputs are adjustable in 10 mV steps down to 2.5 V pk. A user-settable amplitude limit is provided to protect more sensitive system ports and 20 dB attenuators are supplied fitted to the pulse outputs for small-signal and optimum-match applications. 

Step Recovery variable amplitude pulse

The positive (fast rise) and negative (fast fall) pulses are both ground referenced and each pulses in opposite polarity to their user selected amplitude. This amplitude (the ‘mark’) is held for the user-selected pulse width and then returns to ground. Further pulses are prevented for the user set hold-off period and thereafter will repeat at 40 ns after the next received trigger. When the internal clock is selected, the pulse will repeat at the user-set period and holdoff is inactive. An output trigger is generated 40 ns before every pulse, however initiated.

Pulse transition time is typically 55 ps and spectral content (compared with a simulated ideal infinitely fast edge) extends to around 13 GHz @ –10 dB.

The negative (fast fall) pulse can be selected for even faster transition time by selecting ‘fast’ rather than ‘smooth’ mode. Pulse aberration is compromised but transition time is typically 45 ps and spectral content extends to around 14 GHz @ –10 dB.

Typical pulse shape as captured on a PicoScope 9300 20 GHz Sampling Oscilloscope are shown to the right.

Tunnel Diode Head fixed-amplitude pulse

The positive (fast rise) and negative (fast fall) pulses are both ground-referenced and each pulses in opposite polarity to its user-selected amplitude. This amplitude (the ‘mark’) is held for the user-selected pulse width and then returns to ground. Further pulses are prevented for the user-set holdoff period and thereafter will repeat at 40 ns after the next received trigger. When the internal clock is selected, the pulse will repeat at the user-set period and holdoff is inactive. An output trigger is generated 40 ns prior to every pulse, however initiated.

Pulse transition time is typically 55 ps and spectral content (compared with a simulated ideal infinitely fast edge) extends to around 13 GHz @ –10 dB.

The negative (fast fall) pulse can be selected for even faster transition time by selecting ‘fast’ rather than ‘smooth’ mode. Pulse aberration is compromised but transition time is typically 45 ps and spectral content extends to around 14 GHz @ –10 dB. Typical pulse shape as captured on a PicoScope 9300 20 GHz Sampling Oscilloscope is shown to the right.

Features

 PG911 and PG914

  • Integral 50 Ω SMA(f) Step Recovery Diode outputs
  • < 60 ps transition time
  • Dual 2.5 to 6 V variable amplitude outputs
  • ±1 ns in 1 ps steps timing deskew
  • 200 ns to 4 μs pulse width
  • 1 μs to 1 s internal clock period
  • ​< 3 ps RMS jitter relative to external trigger
  • –20 dB 10 GHz SMA(m-f) attenuator included with Step Recovery Diode outputs
 PG912 and PG914
  • External 50 Ω N(m) positive and negative Tunnel Diode pulse heads
  • < 40 ps transition time
  • Dual > 200 mV fixed amplitude outputs
  • ​±200 ps in 1 ps steps timing deskew
  • Inter-series N(f) – SMA(m) adapter included with Tunnel Diode pulse heads

PicoSource PG900 Series applications

TDR applications with a PicoScope 9300 Sampling Oscilloscope

TDR applications with a PicoScope 9300 Sampling Oscilloscope

Controlled over USB from a single PC, the PG900 Pulse Generators can be used with a PicoScope 9300 Sampling Oscilloscope to realize Time Domain Reflectometry with the models that do not integrate that functionality (PicoScope 9301, 9302, 9321 and 9341).

TDR setup with PicoScope 9300 Sampling Oscilloscope

Single-ended measurements can be performed using just one pulse source and an oscilloscope channel.

TDT applications with a PicoScope 9300 Sampling Oscilloscope

TDT applications with a PicoScope 9300 Sampling Oscilloscope

Controlled over USB from a single PC, the PG900 Pulse Generators can be used with a PicoScope 9300 Sampling Oscilloscope to measure Time Domain Transmission with those models that do not include that function (PicoScope 9301, 9302, 9321 and 9341). They may also add the versatility of a remotely placed signal generator for long line or installed system testing with any of the PicoScope 9300 models.

TDT setup with any PicoScope 9300 Sampling Oscilloscope

Single-ended measurements can be performed using just one pulse source and an oscilloscope channel.

 
TDT and crosstalk with a PicoScope 9341 Sampling Oscilloscope

TDT and crosstalk with a PicoScope 9341 Sampling Oscilloscope

Controlled over USB from a single PC, the PG900 Pulse Generators can be used with a PicoScope 9341 four-channel Sampling Oscilloscope for simultaneous Time Domain Transmission and Crosstalk assessment.

TDT and crosstalk setup with PicoScope 9341 Sampling Oscilloscope

Single-ended measurements can be performed with a two-channel Sampling Oscilloscope and differential measurements can also be tackled by first measuring transmission and then changing connections for crosstalk measurement. Unconnected ports should always be correctly terminated.

Ordering

 

MODEL ORDER CODE PULSE GENERATOR
PicoSource PG911 PP977 50 Ω SMA(f) < 60 ps differential pulse outputs,2.5 V to 6 V variable amplitude
PicoSource PG912 PP978 50 Ω N(m) < 40 ps positive and negative tunnel diode pulse heads,> 200 mV fixed amplitude
PicoSource PG914 PP979 Dual-mode generator with both of the above outputs

Downloads

PicoSource PG900 Pulse Generators Data Sheet

Specification

 

PicoSource PG911 and PG914

Pulse outputs Positive-going (fast rise) and negative-going (fast fall) outputs returning to 0 V.
Adjustable amplitude and timing parameters. Fast transition on leading edge.
Output impedance 50 Ω
Output connector SMA(f)
Output amplitude Adjustable 2.5 V to 6 V in 10 mV steps
Output accuracy ±10%
Output amplitude limit 2.5 V to 6 V, adjustable in 100 mV increments
Duty cycle limit 50% maximum (for 2.5 V to 4 V amplitude)
20% maximum (up to 6 V amplitude)
Differential deskew range Adjustable in 1 ps steps over 2 ns range
Positive or negative-going, smooth mode: Negative-going, fast mode:
Pulse transition time < 60 ps (10% to 90%) (smooth mode) < 50 ps (10% to 90%)
Pulse aberrations < +20%, –10% for first 2 ns < (+40%, –10%)
< ±7% to 10 ns
< ±2% to pulse width –50 ns
Trailing edge transition time < 8 ns (10% to 90%)

PicoSource PG912 and PG914

PS9040 Positive tunnel diode pulse head Positive-going (fast rise) output on < 70 mV pedestal.
Fixed amplitude and adjustable timing parameters.
Fast transition on leading edge.
PS9041 Negative tunnel diode pulse head Negative going (fast fall) output on < –70 mV pedestal.
Fixed amplitude and adjustable variable timing parameters.
Fast transition on leading edge.
Output impedance 50 Ω, ±2 Ω
Output connector N(m)
Output amplitude Fixed 200 mV
Output accuracy ±25%
Differential deskew range Adjustable in 1 ps steps over 200 ps minimum, 300 ps typical
Pulse transition time < 40 ps (10 % to 90%)
Pulse aberrations < ±20%, for first 2 ns
< ±7% to 15 ns
< ±2% to (pulse width – 50 ns)
Trailing edge transition time < 8 ns (10% to 90%)
Dimensions (each pulse head) 80 mm x 28 mm x 25 mm
Weight (each pulse head) 125 g

All models and outputs

Pulse trigger source External input, manual single shot event or internal clock
Jitter relative to leading edge 3.0 ps RMS typical. 3.5 ps RMS maximum.
Post-trigger delay to pulse leading edge Fixed 42 ns ±2 ns
Allows leading-edge capture on sampling oscilloscopes
Pulse width and accuracy 200 ns to 4 µs ± 10% ± 50 ns, user adjustable in steps of 25 ns
Pulse width jitter < 150 ppm of width RMS
External trigger hold-off Adjustable 1 μs to 1.3 ms in steps of 200 ns, to maximum of 345 ms in steps of < 15 ppm

 

Period and accuracy Adjustable 1 µs to 1 s, ±100 ppm ±10 ns in steps of 200 ns
Impedance 50 Ω ±1%
Connector SMA(f)
Maximum input level +16 dBm, or ±2 V DC or AC pk
Bandwidth 1 GHz, DC coupled
Trigger polarity Selectable rising or falling edge
Trigger level Selectable –1 V to +1 V in steps of 1 mV
Sensitivity < 50 mV pk-pk DC to 100 MHz, rising linearly to 100 mV pk-pk at 1 GHz
Minimum pulse width 500 ps at 100 mV pk-pk
EXTERNAL TRIGGER OUTPUT SPECIFICATION
Trigger output pulse Fixed amplitude and timing parameters, positive edge polarity, trigger is leading edge
Impedance 50 Ω, ±0.5 Ω
Connector SMA(f)
Amplitude and offset > 700 mV fixed, on logic low of 0 V ± < 100 mV
Pulse width 500 ns, ±100 ns
Trigger to trigger output delay 4 ns, ±1 ns
Trigger to trigger output jitter 2.5 ps rms typical. 3 ps rms maximum.
Transition time < 400 ps (10% to 90%)
AC to DC adaptor 5 V ±5% at 1.6 A, 8 W, universal plug (adaptor included)
PC connection USB 2.0 (USB 1.1 and USB 3.0 compatible), 1.8 m USB 2.0 lead included
PC requirements Windows XP SP3 to Windows 8
Operating temperature range +5 °C to +35 °C
Storage temperature range –20 °C to +50 °C
Temperature range for stated specifications +15 °C to +25 °C or TCAL (temperature of calibration) ±5 °C
Operating humidity range < 85% RH (non-condensing) at +25 °C
Storage humidity range < 95% RH (non-condensing)
Dimensions (instrument) 190 mm W x 180 mm D x 40 mm H
Weight (instrument) 560 g

* Specifications describe guaranteed performance over the stated temperature range and apply after the instrument’s temperature has been stabilized in 1 hour of continuous operation. All specifications are subject to change without notice.

* Factory calibration cycle. For optimum performance, the instrument should have a complete verification of specifications once every 12 months.

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