The Tektronix 7B53A and 7B53AN is a 100 MHz dual time base plug-in for 7000-series scopes. It is similar to the 7B52 which is much more rarely found. While the 7B52 has a separate mode switch, this is integrated into the TIME/DIV switch in the 7B53A.
The 7B53AN is electrically identical to he 7B53A but omits the circuits needed to drive the alphanumeric readout system provided in 7000-series mainframes. The TD-1085/U is a military designation for the 7B53AN11 which was used in the AN/USM-281C military version of the 7603 scope.
There does not appear to have been a product sold called simply "7B53". There is a 7B53N, a 7B53A, and a 7B53AN.
|Sweep rates||50 ns/Div to 5 s/Div in 1—2—5 sequence (5 ns with ×10 magnification)|
|Deflection||10 mV/Div, 100 mV/Div or 1 V/Div, up to 2 MHz|
|Sensitivity||0.3 Div or 100 mV up to 10 MHz, 1.5 Div or 500 mV up to 100 MHz|
|Coupling||DC, AC (> 30 Hz), AC LF REJ (> 30 kHz), AC HF REJ (30 Hz — 150 kHz)|
|Input impedance||1 MΩ // 20 pF|
|Jitter||< 1 ns at 75 MHz|
- TekScope Vol. 7 No. 5, 1975 p.15+: Dave McCullough, Delayed gate aids oscilloscope digital measurements
Delayed Sweep Gate output
When the delayed timebase trigger source switch is set to INT (pushed in) and the internal connector P613 is in the active position, the DLY'D TRIG IN connector becomes a Delayed Sweep Gate output. This is useful e.g. to connect to a 7D15's arming inputs, or a 7D12/M2's external trigger input. See the 1975 TekScope article linked above.
Through an internal jumper, the front-panel variable control (red knob) can be selected to vary either the main sweep, the delayed sweep or the main sweep hold-off. See the 1975 TekScope article linked above.
Use as Delayed Timebase
The 7B53A only works in "triggered after delay" mode when used as a delayed timebase, unlike e.g. the 7B92.
The 7B53 supports X-Y mode by selecting the "Ampl" position on the Time/Div switch. The X signal can be picked up from a vertical plug-in via the internal trigger path or applied via the "Main Trig In or Amp In" input, as determined by the Trigger Source switch setting. Sensitivity on the external input is 100 mV/Div, which can be increased to 10 mV/DIv by selecting the x10 magnifier, or decreased to 1 V/Div by pushing the EXT÷10 button.