Tektronix SD24 TDR Sampling Head

Features

• TDR/Sampling Head
• Dual-channel, Differential TDR
• 20 GHz Bandwidth
• 35 ps Reflected Rise Time
• Line Impedance and Crosstalk Characterization

The SD-24 is a dual-channel TDR/Sampling Head. This sampling head has a rise time of 17.5 ps or less, with a typical 20 GHz equivalent bandwidth. Each channel of the SD-24 is also capable of generating a fast rising step for use in Time Domain Reflectometry (TDR). In TDR mode, the acquisition portion of the sampling head monitors the incident step and any reflected energy. The reflected rise time of the TDR step is 35 ps or less. The polarity of each channel's TDR step can be selected independently of the other channel. This allows for differential or common-mode testing of two coupled lines, in addition to the independent testing of isolated lines. The SD-24 can be used to characterize crosstalk by using the TDR step to drive one line while monitoring a second with the other channel. The "filter" function on the CSA 803C/11801C can be used with TDR or crosstalk measurements to characterize a system at a slower rise time.

Displayed Rise Time.

Incident - 28 ps typical, 10% to 90%, at +250 mV or -250 mV output, elsewhere ±1%.

Reflected - 35 ps or less, 10% to 90%, at +250 mV or -250 mV output. TDR Step Amplitude - Adjustable to ±250 mV (polarity of either step may be inverted).

Time Coincidence Between TDR steps - Adjustable to less than 1 ps. Source Resistance - 50 Ohm ±0.5 Ohm.

Aberrations (at ±250 mV amplitude) - The following are TDR aberrations. 10 ns to 20 ps before step: ±3% or less. <300 ps after step: +10%, -5% or less. 300 ps to 5 ns after step: ±3% or less. Elsewhere: ±1% or less.

Environmental and Safety Characteristics

(11801C, CSA 803C, SD-Series Heads)

Temperature - Operating: 0°C to +50°C; nonoperating: -40°C to +75°C.

Altitude, Vibration, Shock, Bench Handling - Operating and nonoperating: meets MIL-T-28800C, Type III, Class 5.