BJTU Fall 2018 0 Problems 6-1 The amplitude of the modulated signal is 2.4V, the maximum...
Communication systemProblems A 25 MHz carrier is modulated by a 400 Hz audio sine wave If the carrier voltage 4 V and the maximum deviation is 10 KHz, write the equation of this modulated wave for FM. If the modulating frequency is now changed to 2 KHz, all else remaining constant, write the new equation for FM2. In an FM system, when the audio frequency (AF) is 500 Hz and the AF voltage is 2.4 V, the deviation is 4.8 KHz....
1 2 4. The amplitude modulation signal is given by the following expression and is applied to 75 load. Vam(t) = 10 sin (21fct) - 2.5 cos (1500krt) + 2.5 cos (1450krt) V Determine: a) Modulation index b) The frequency of the carrier and the information signal c) The bandwidth d) The total power e) The transmission power efficiency be ar e 5. One of the inputs to a frequency modulator is a 250 kHz carrier signal with amplitude of...
Question 4: (20 points) An FM signal is modulated with message m(t)Am cos(2Tmt). The measured amplitude spectrum, SPM(f), is shown below: Amplitude spectrum of the frequency modulated signal 2 -2 5000 4000 3000 2000 -1000 1000 2000 3000 4000 5000 frequency f [Hz] a) What is the carrier frequency fe? b) What is the message frequency fm c) What is the FM modulation index Bf? Is it a narrowband or a wideband signal? d) Using Carson's rule, estimate the transmission...
Consider an FM system where the modulated signal is s(t) = 10 cos (2πfct + 2πkf∫0t m(τ)dτ)where the carrier frequency is fc = 100 MHz. The modulation signal is m(t) = 10 cos(2πfmt), where fm = 3 kHz. (a) Assuming that kf = 10, what is the approximate bandwidth of s(t)? (b) Find the instantaneous frequency fi(t) of s(t). What are the maximum and minimum values of fi(t) ?
#3) For an AM-TC signal, the positive envelope of the modulated signal is within the range of 8V and 12V. Find the modulation index. Also, if the baseband signal is +2 V, 4 kHZ, and carrier is 40 kHz, show the frequency spectrum with all values
5. Consider the following message signal: -2 Assume that the carrier frequency is f are kr 105, kp 25 respectively. 108 Hz, and frequency and phase deviation constants Find the maximum and minimum frequency deviation for FM, and sketch the FM wave for a duration of 103 seconds shown in the above figure (5 points). a. b. Find the maximum and minimum frequency deviation for PM, sketch the PM wave for a duration of 103 seconds shown in the above...
1.) Angle Modulation can be subdivided into phase modulation (PM) and frequency modulation (FM). Highlight the differences between FM and PM. What is meant by the term instantaneous frequency? 2.) Describe what is meant by the term "Zero-Crossings" of a FM or PM wave. 3.) Is PM and/or FM a linear modulation technique? Explain. 4.) Describe one important advantage that angle modulation has over amplitude modulation. Describe one distinct disadvantage that angle modulation has over amplitude modulation. 5.) Describe the...
5. Consider the following message signal: m(t) -2 .3 10 Assume that the carrier frequency is f are kf = 105, kp-25 respectively. 108 Hz, and frequency and phase deviation constants Find the maximum and minimum frequency deviation for FM, and sketch the FM wave for a duration of 103 seconds shown in the above figure (5 points). a. b. Find the maximum and minimum frequency deviation for PM, sketch the PM wave for a duration of 103 seconds shown...
A single-tone angle-modulated signal is given by ?(?) = 20cos[6 ∗ 108 ? + 40 sin(1000??)] Assume that the function is an FM signal. Determine (a) the unmodulated carrier frequency, (b) the modulating frequency, (c) the modulation index, and (d) the maximum frequency deviation. Express all frequencies in hertz. (e) Determine the average power dissipated in a 50Ω resistor
When frequency division multiplexing (FDM) is used to aggregate several modulated channels together, no separation between channels (i.e., use of guard channels) is required. True False Regarding amplitude modulation (AM), if the AM index, µ, is greater than 1, then the modulated passband signal will begin to show signs of signal distortion. True False Given the following AM modulated signal, determine the occupied frequency bandwidth (note: assume double-sideband large carrier (DSB-LC): s(t) = 4[1+0.95 cos(2π3000t)] cos(2π100E9t) a. Frequency bandwidth =...