DC503A
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The Tektronix DC503A is a 125 MHz, 8-digit frequency counter plug-in for the TM500 system.
It replaced the DC503 in 1981.
Key Specifications
| Resolution | 8 digits |
|---|---|
| Frequency Range | DC (AC coupled: 10 Hz) to ≥125 MHz |
| Impedance | 1 MΩ paralleled by approx. 27 pF |
| Sensitivity | 20 mVRMS sine to 100 MHz, 35 mVRMS sine to 125 MHz |
| Max Input Voltage | 1× Atten: 200 Vpeak, 400 Vp-p @ DC − 50 kHz; 200 Vpeak, ≤(20/f) Vp-p @ 50 kHz − 1.33 MHz; 200 Vpeak, ≤15 Vp-p @ 1.33 – 125 MHz |
| Max Input Voltage | 5× Atten: 200 Vpeak, 400 Vp-p @ DC − 5 MHz; 200 Vpeak, ≤(2000/f) Vp-p @ 5 − 100 MHz; 200 Vpeak, ≤20 Vp-p @ 100 – 125 MHz |
Options
- Opt. 01 — OCXO
Links
- Tektronix DC503A Frequency Counter OCXO Mod by NFM @ YouTube
- Tek Component News No.278, Feb 1980 – page 13, New Tektronix lever switch
Documents Referencing DC503A
| Document | Class | Title | Authors | Year | Links |
|---|---|---|---|---|---|
| 070-2088-04.pdf | Book | TM500 Series Rear Interface Data Book | 1985 | AA501 • AF501 • AM501 • AM502 • AM503 • AM511 • DC501 • DC502 • DC503 • DC503A • DC504 • DC505 • DC505A • DC508 • DC508A • DC509 • DC510 • DC5009 • DC5010 • DD501 • DL502 • DM501 • DM501A • DM502 • DM502A • DM505 • DM5010 • FG501 • FG501A • FG502 • FG503 • FG504 • FG507 • FG5010 • LA501 • LA501W • WR501 • MR501 • PG501 • PG502 • PG505 • PG506 • PG507 • PG508 • PS501 • PS502 • PS503 • PS503A • PS505 • PS5010 • RG501 • SC501 • SC502 • SC503 • SC504 • SG502 • SG503 • SG504 • SG505 • SW503 • TG501 • TR501 • TR502 • MI5010 • MX5010 • SI5010 |
Rear interface
| 27B − Decimal point | |
| 26B – Remote Start | 26A − /Reset |
| 25A − TS1 (digit select 1, MSD) | |
| 24B − Scan clock out | |
| 23B − Overflow | |
| 22B − Ch.B Level | 22A − Ch.A Level |
| 21B − BCD out 2 | 21A − TTL Clock Input |
| 20B − BCD out 8 | 20A − BCD out 4 |
| 19B − Latch Out (Data Good) | 19A − BCD out 1 |
| 17B – Ch B Input | 17A – Ch A Input GND |
| 16B – Ch B Input GND | 16A − Ch A Input |
| 15B – 10 MHz Ref Out | 15A – Clock GND |
| 14A − External Clock In |
Internals
The DC503A is implemeted in a mix of ECL, TTL, and MOS ICs. uses an LS7031 6-digit counter IC, and two 74S288 PROMs that encode decimal point position and annunciators.
Pictures
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DC503A
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DC503A
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DC503A left internal
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right internal
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left internal (Opt.01)
Components
Some Parts Used in the DC503A
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 2N4249 | 151-0342-00 | Discrete component | PNP Si low noise amp. | DC501 • DC502 • DC503 • DC503A • DC504 • DC504A • DC505 • DC505A • DC508 • DC508A • DC509 • DC510 |
| 74S288 | Monolithic integrated circuit | 32×8 PROM | DC503A • PM110 |