【正文】 andwidth possible b) Low noise figure c) Input/output impedance not dependent on devices as long as device impedances are equal 2. Why is there a frequency term in the equation for freespace path loss? a) There is no frequency term b) Atmospheric absorption c) Antenna geometry requires it 3. If an amplifier has a noise temperature of 60K, what is its noise figure for an ambient temperature of 290K? a) dB b) 80 dB c) dB 4. What is a primary advantage of offsetquadraturephaseshiftkeying (OQPSK) over standard QPSK? a) Greater data rates possible b) Greater spectral efficiency c) More constant envelope power 5. A mixer has the following input frequencies: RF = 800 MHz, LO = 870 MHz. The desired output frequency is 70 MHz. What is the image frequency? a) 940 MHz b) 1670 MHz c) 140 MHz 6. What is the spuriousfree dynamic range of a system with IP3 = +30 dBm and a minimum discernible signal (MDS) level of 90 dBm? a) 80 dB b) 120 dB c) 60 dB 7. A spectrum analyzer displays a ponent at 10 MHz 0 dBm, 30 MHz 10 dBm, 50 MHz 14 dBm, 70 MHz 17 dBm, and all of the other odd harmonics until they disappear into the noise. What was the most likely input signal that caused the spectrum? a) A 10 MHz square wave (0 Vdc) b) A 10 MHz triangle wave (0 Vdc) c) A 10 MHz cosine wave (0 Vdc) 8. On which side of a rectangular waveguide is an Ebend made? a) The long dimension b) The short dimension c) The inside 9. During a work analyzer calibration, why are both a short circuit and an open circuit used? a) They average to 50 ohms in an RF system b) To determine the characteristic impedance of the measurement system c) Both are easy to produce to at high accuracy 10. What is the first harmonic of 1 GHz? a) 1 GHz b) 2 GHz c) 10 GHz RF Quiz 4 1. Which of the following can cause frequency intermodulation products in a system? a) Only semiconductor junctions like diodes and transistors (amplifiers) b) Cable connectors, bolted or riveted antenna panels, isolators and circulators c) Both a) and b) 2. What is the melting temperature of standard 60/40, tin/lead solder? a) 100176。C (482176。 amp 10. At what frequency is electromagic energy maximally absorbed due to oxygen in the atmosphere? a) 22 GHz b) Only water in the atmosphere absorbs electromagic energy c) 63 GHz RF QUIZ 5 This quiz tests your recognition of logos from panies* that are leaders in the RF industry. In some cases, part of the standard logo was cropped because it had the pany name included. Printing out this page to fill in the blanks is probably the best way to go about this puzzle. Hover your cursor over a logo to see a hint as to what type of product it manufactures. _______________ _______________ ? American Technical Ceramics (ATC) ? Piconics ? Channel Microwave ? Marki Microwave ? Scientific Atlanta ? Anadigics ? National Instruments _______________ _______________ _______________ _______________ _______________ _______________ _______________ _______________ ? Remec ? Analog Devices ? Datel ? Andrew Corporation ? Hittite Microwave ? Delta ? Power Cube ? Agilent Technologies ? Synergy Microwave ? Power One ? Cypress Semiconductor ? Connecticut Microwave ? Miteq ? Vicor ? National Semiconductor ? Maury Microwave ? Cinch ? Stanford Microdevices ? Huber+Suhner ? Johanson Dielectrics ? Sage Labs ? Ansoft ? Atlantic Microwave ? Intusoft ? Dallas Semiconductor ? Merrimac Industries ? Applied Radio Labs ? Texas Instruments ? Trilithic ? Rohde amp。 b) frān?l39。10% 9. What serious problem is monly caused with leadfree, tinalloy solders a) Tin whiskers b) Cold flowing c) Spontaneous bustion RF Quiz14 1. Who from this list is usually credited with being the first to experiment with high frequency oscillator circuits? a) Benjamin Franklin b) Nikola Tesla c) Edwin Armstrong d) Albert Einstein 2. In the four basic oscillator circuits shown below, what is the primary function of the transistor? a) Frequency control b) Amplitude control c) Compensation for tank circuit losses d) Isolation 3. Which type of oscillator circuit is shown to the right? a) Colpitts oscillator b) Clapp oscillator c) Hartley oscillator d) Pierce oscillator 4. Which type of oscillator circuit is shown to the right? a) Colpitts oscillator b) Clapp oscillator c) Hartley oscillator d) Pierce oscillator 5. Which type of oscillator circuit is shown to the right? a) Colpitts oscillator b) Clapp oscillator c) Hartley oscillator d) Pierce oscillator 6. Which type of oscillator circuit is shown to the right? a) Colpitts oscillator b) Clapp oscillator c) Hartley oscillator d) Pierce oscillator 7. Which factor is most important in maintaining spectral purity in an oscillator circuit? a) Overall circuit Q (quality factor) b) Component sizes c) Q of individual ponents d) Transistor gain 8. What does the term frequency pulling refer to? a) Change in frequency due to power supply variations b) Change in frequency due to load variations c) Change in frequency due to thermal variation d) All the above 9. In a phaselocked loop (PLL) oscillator circuit, what does the phase detector do? a) Detects phase b) Compares relative phase between the reference input and oscillator output and introduces a shift as necessary to maintain phase coherence c) Injects random phase shifts at the input to stabilize the output frequency d) Phase detectors are not used in PLL circuits