Electronics Study Notes: Universal Gates & TETRA

Study Notes

Question Bank - Study Notes

Universal Gates:
- The most widely used universal gates are OR and AND gates.
Tetra Frequencies:
- Frequencies allocated for Tetra-based communication systems are 260-300 MHz & 410-430 MHz, and 380-400 MHz & 410-430 MHz.
Universal Emergency Communication (UEC) Frequency:
- UEC operates on 196.23-456.56 MHz frequency.
- It also operates on 146.2-151.45 MHz frequency..
TETRA Full Form:
- TETRA stands for Telecom terrestrial Radio.
Instrument Error:
- Instrument error is normally given as the percentage of the measured value.
Digital Voltmeter Converter:
- The basic A-to-D converter in a digital voltmeter is a voltage-to-time converter.
Voltmeter Sensitivity:
- A voltmeter using a 50 microampere meter has a sensitivity of 20 kilo ohms per volt.
Internal Resistance of Voltmeter:
- An instrument with 1000 ohms per volt sensitivity on a 100-volt scale will have an internal resistance of 100,000 ohms.
Voltmeter Reading Error:
- Increasing the voltmeter resistance will increase or decrease the reading error, depending on the value of measurement and voltmeter resistance.
Digital Voltmeter Readout Precision:
- A 4.5-digit digital voltmeter can read up to 1.9999 volts.
Consultative Committee for International Telephony and Telegraphy (CCITT):
- CCITT stands for Consultative Committee for International Telephony and Telegraphy.
Measurement System Components:
- In a measurement system, a transducer is the input element.
International Telecommunication Union (ITU):
- ITU stands for the International Telecommunication Union.
dBm Value:
- 33 dBm is equal to 2 watts.
Megger Instrument Type:
- A megger is typically a moving iron type instrument.
Measuring Sets:
- Transmission measuring sets are used for measuring signal levels and transmission loss.
Open Shortest Path First (OSPF):
- OSPF stands for Open Shortest Path First.
Insulation Test Instrument:
- A Megger is a common instrument used to check insulation.
Capacitance Permitted in Loading:
- The maximum capacitance allowed in a loading section is 20pF
Parallel Resistor Value:
- Two 8-ohm resistors in parallel result in 4 ohms.
Switchboard Cable Use:
- Telecom switchboard cables are used for both indoor and outdoor wiring.
Cable Impedance:
- The characteristic impedance of a switchboard cable is 600 ohms.
UTP Cable Expansion:
- UTP stands for Unshielded Twisted Pair.
Quad Cable Unbalance:
- Unbalance in capacitive coupling in quad cables causes distortion and crosstalk.
Earth Coupling Unbalance:
- Unbalance in earth coupling in VF circuits causes crosstalk and noise.
Quad Cable Capacitance Unbalance:
- The capacitance unbalance between side circuit 2 of quad number 1 relative to side circuit 1 of quad number 1 is K12.
- The maximum allowable capacitance unbalance in a loading section is 20pF
Resistor Connections:
- Two 8-ohm resistors in series produce 16 ohms.