7L13: Difference between revisions

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{{Spec|Input frequency      | 100 kHz – 1.8 GHz}}
{{Spec|Input frequency      | 100 kHz – 1.8 GHz}}
{{Spec|Span                | 200 Hz/Div – 100 MHz/Div}}
{{Spec|Span                | 200 Hz/Div – 100 MHz/Div}}
{{Spec|Sweep                | 1 μs/Div to 10 s/Div (1-2-5), manual, external}}
{{Spec|Sweep                | 1 μs/Div to 10 s/Div (1−2−5), manual, external}}
{{Spec|Resolution bandwidth | 30 Hz – 3 MHz in decade steps}}
{{Spec|Resolution bandwidth | 30 Hz – 3 MHz in decade steps}}
{{Spec|Sensitivity          | −128 dBm at 300 Hz to −80 dBm at 3 MHz }}
{{Spec|Sensitivity          | −128 dBm at 300 Hz to −80 dBm at 3 MHz }}
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==Internals==
The input signal passes a 0 to 60 dB step attenuator, a 1.8 GHz low-pass filter, and a 3 dB isolation pad before the 1<sup>st</sup> mixer, with a 1<sup>st</sup> LO frequency between 2.095 GHz and 3.895 GHz.  At spans of 50 kHz/Div and below, the
1<sup>st</sup> LO (a YIG oscillator) is fixed (stabilized by a PLL) and the 2<sup>nd</sup> LO is swept.
The 1<sup>st</sup> IF filter is 10 MHz wide, centered at 2.095 GHz.  With a 2<sup>nd</sup> LO at 2.2 GHz, the signal is mixed to a 105 MHz IF, amplified, filtered again (105±1.5 MHz)and mixed down to 10 MHz (3<sup>rd</sup> LO at 95 MHz).
At the 10 MHz 3<sup>rd</sup> IF, resolution filters (300 kHz L/C, 30 kHz, 3 kHz or 300 Hz crystal filters) can be selected.  The detector (discrete log amplifier) and video filters follow.
The digital frequency readout is a DVM ([[Fairchild 3814]]) working off the the YIG oscillator control voltage, not a frequency counter, which is why it needs to be calibrated before use.
Custom integrated circuits used: [[155-0035-00|155-0035-00 quad opamp]], [[155-0042-02|155-0042-02 Miller Integrator]], [[155-0056-00|155-0056-00 Sweep Control]], [[155-0088-00|155-0088-00 Legend Generator]].


==Pictures==
==Pictures==

Revision as of 08:21, 19 February 2021

Template:Plugin Sidebar 2

The Tektronix 7L13 is a 1 kHz to 1.8 GHz Spectrum Analyzer plug-in for 7000-series scopes.

It is similar to the 7L12 but occupies three module bays, adds a marker function, offers resolution bandwidth down to 30 Hz, and improves sensitivity by 10 dB. It also displays the center frequency in the CRT readout as well as on a LED display.

The TR502 tracking generator is designed to work with the 7L13 up to 1.8 GHz.

Key Specifications

Input frequency 100 kHz – 1.8 GHz
Span 200 Hz/Div – 100 MHz/Div
Sweep 1 μs/Div to 10 s/Div (1−2−5), manual, external
Resolution bandwidth 30 Hz – 3 MHz in decade steps
Sensitivity −128 dBm at 300 Hz to −80 dBm at 3 MHz
Vertical scale 10 dB/Div, 2 dB/Div or linear
Reference level −110 dBm – +30 dBm in 10 dB steps
Video filters 30 kHz, 300 Hz or 10 Hz
Features
  • Automatic phase lock
  • CRT readout of center frequency
  • UNCAL indicator
  • built-in calibrator 50 MHz, −30 dBm
  • Base line clipper

Links

Prices

Year 1974 1976 1980
Catalog price $6,500 $7,500 $10,500
2020 Dollars $34,100 $34,100 $33,000

Internals

The input signal passes a 0 to 60 dB step attenuator, a 1.8 GHz low-pass filter, and a 3 dB isolation pad before the 1st mixer, with a 1st LO frequency between 2.095 GHz and 3.895 GHz. At spans of 50 kHz/Div and below, the 1st LO (a YIG oscillator) is fixed (stabilized by a PLL) and the 2nd LO is swept.

The 1st IF filter is 10 MHz wide, centered at 2.095 GHz. With a 2nd LO at 2.2 GHz, the signal is mixed to a 105 MHz IF, amplified, filtered again (105±1.5 MHz)and mixed down to 10 MHz (3rd LO at 95 MHz).

At the 10 MHz 3rd IF, resolution filters (300 kHz L/C, 30 kHz, 3 kHz or 300 Hz crystal filters) can be selected. The detector (discrete log amplifier) and video filters follow.

The digital frequency readout is a DVM (Fairchild 3814) working off the the YIG oscillator control voltage, not a frequency counter, which is why it needs to be calibrated before use.

Custom integrated circuits used: 155-0035-00 quad opamp, 155-0042-02 Miller Integrator, 155-0056-00 Sweep Control, 155-0088-00 Legend Generator.

Pictures