7L13
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 |
|
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.
