1L5

Template:Plugin Sidebar 2 The Tektronix 1L5 is a low-frequency spectrum analyzer for 500-series scopes. It is very similar to the 3L5.

Its center frequency is set on a trio of rotary switches and can range from 50 Hz to 990 kHz. Minimum resolution bandwidth is 10 Hz. It has a 1 MΩ input resistance.

Type 1L5 was sold from 1967 until the end of the classic plug-in scope line. Not particularly accurate in either frequency, bandwidth, or amplitude, it was no match for HP's 141T/8556A/8552B combination in performance, but it was a small fraction of the price.

Although Type 1L5 can operate in any 500-series scope*, it is most useful by far in the Type 549 storage mainframe which allows slow sweeps needed to match the narrower resolution bandwidths.

In conjunction with the 015-0107-00 "Swept Frequency Generator" (tracking generator), the 1L5 can also measure frequency response.

* 531/535/541/545 need a wiring mod to alleviate vertical amp instability.

Pictures

549 works fine with 1L5
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rear
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front
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1L5
Block Diagram
Attenuators and Input
Center Frequency Switching
Swept Frequency Generator
Variable Resolution Amplifier
Dispertion Warning Light
Output Amplifier
Calibrator
Interconnecting Plug and Power Distribution
Preproduction 1L5 (serial A01)
Preproduction 1L5 (serial A01)
Preproduction 1L5 (serial A01)
Measured frequency response of 3MHz filter from P90 to P280 with Q290 removed to disable 3.1 MHz oscillator, but powered up