SW503

Manuals – Specifications – Links – Pictures

The Tektronix SW503 is a sweep generator plug-in for the TM500 system.

It provides a swept frequency of 1 MHz to 400 MHz with variable sweep rate, width, and output level. Crystal-controlled harmonic oscillators provide comb markers with 1 MHz, 10 MHz, or 50 MHz separation. When used with a DC502 Option 7 counter, a frequency marker dot can be positioned anywhere within the frequency range of the SW503, and the frequency of the marker can be read directly on the counter.

Key Specifications

Frequency range	1 to 400 MHz
Sweep width	200 kHz to 400 MHz
Sweep time	10 ms to 100 s, decade steps plus vernier
Output	−40 to +10 dBm into 50 Ω
Horizontal output	0.5 Vp-p
Fixed markers	frequency comb with 1, 10, or 50 MHz base frequency
Variable marker	1 to 400 MHz, digital readout on a DC502 Opt.07 or DC508/DC508A Opt.07 counter
Features	Amplitude control input (0 – 10 V) Frequency control input (0 – 10 V) Sweep trigger input (10 V pulse ≥1 μs)
Options	Opt. 01 – 75 Ω output impedance Detector – 118-0070-00 (50 Ω), 118-0071-00 (75 Ω)

Internals

A control voltage tunes a sweep oscillator from 1001 MHz to 1400 MHz. This frequency is mixed with a fixed 1 GHz signal to produce the 1 MHz to 400 MHz output. A 50 MHz oscillator with ÷5 and ÷10 dividers drives a step-recovery diode at the selected marker frequency to generate a frequency comb. This is mixed with a sample of the sweep frequency to generate a series of zero beats that are detected and superimposed on the detector input signal for the V display output.

A comparator stops the sweep integrator when the control voltage reaches the level set by the DOT POSITION control. At this point, the Start Count line (rear interface B18) signals the counter to start counting, which sets the counter /GATE signal (rear interface A18) low. When the count is complete, /GATE goes high again, which causes the sweep to resume.

The Rear Interface manual says,

Other counters could be modified by the user to work with the dot marker scheme.

Only two of the lines are required, the start count (18Β) to trigger the counter, and the negative gate (18Α) from the counter to resume the sweep.

In addition, contact 17Β would have to be grounded on the sweep generator.

Rear Interface

Connector Pin	Signal
28B	Y axis output (common on 28A)
27B	X axis output (common on 27A)
24B	Trigger input (common on 25B)
21B	Amplitude control input (0 – 10 V), common on 22B
20B	Frequency control input (0 – 10 V), common on 22B
18B	Start Count (0/+5 V; positive pulse to trigger the counter)
18A	Gate (0/+5 V; negative gate from counter)
17B	Counter Identify (grounded when counter is installed)
16B	Phase Lock Logic (grounded by the SW503)
15B	CW Mode Logic (+5 V: dot marker function; 0 V: normal counter function)
14B	Sweep Generator Identify (grounded by the SW503)

Pictures

External

• 
• 

  SW503 in TM515 with other TM500 gear

• 
• 

SW503 Opt.1

• 
• 
• 
• 
• 

SW503B

• 

  SW503B catalog picture

Internal

• 
• 

Components

Some Parts Used in the SW503

(no results)