Aufgaben:Exercise 1.1Z: VHF II Broadcasting - Revision history

Reed: /* Solution */

2022-03-23T16:18:12Z

Solution

Reed: /* Questions */

2022-03-23T16:17:52Z

Questions

Reed at 09:58, 24 November 2021

2021-11-24T09:58:31Z

Reed at 13:07, 2 November 2021

2021-11-02T13:07:24Z

Guenter at 10:43, 1 November 2021

2021-11-01T10:43:16Z

Guenter at 10:31, 1 November 2021

2021-11-01T10:31:02Z

Guenter at 10:29, 1 November 2021

2021-11-01T10:29:51Z

Guenter: Guenter moved page Aufgaben:Exercise 1.1Z: VHF Broadcasting to Aufgaben:Exercise 1.1Z: VHF II Broadcasting

2021-11-01T10:24:27Z

Guenter moved page Exercise 1.1Z: VHF Broadcasting to Exercise 1.1Z: VHF II Broadcasting

Guenter at 10:24, 1 November 2021

2021-11-01T10:24:11Z

Reed at 14:21, 28 October 2021

2021-10-28T14:21:04Z

@@ Line 62: / Line 62: @@
-'''(3)'''&nbsp; <u>Answers 1 und 4</u> are correct:
+'''(3)'''&nbsp; <u>Answers 1 and 4</u> are correct:
 *The channel spacing and thus the bandwidth&nbsp; $\text{300 kHz}$&nbsp; available for a channel is significantly larger in the VHF range than for long, medium and short wave broadcasting.&nbsp; Although the frequency modulation used in FM broadcasting is characterized by better quality,&nbsp; it also requires more bandwidth.
 *For comparison,&nbsp; in the medium wave range,&nbsp; amplitude modulation and a channel spacing of&nbsp; $\text{9 kHz}$&nbsp; is always used&nbsp; (in Europe) &nbsp; <br>&rArr; &nbsp; the source signal bandwidth is&nbsp; $B_{\rm LF} = \text{9 kHz/2 = 4.5 kHz}$.

@@ Line 41: / Line 41: @@
 $K \ = \ $ { 68 1% }
-{Which of the follwoing statements are true?
+{Which of the following statements are true?
 |type="[]"}
 + The VHF channels have higher bandwidth than those for long-wave, medium-wave and short-wave broadcasting.

@@ Line 23: / Line 23: @@
 ''Hints:''
-*This exercise belongs to the chapter &nbsp; [[Modulation_Methods/Zielsetzung_von_Modulation_und_Demodulation|Objectives of modulation and demodulation]].
+*This exercise belongs to the chapter &nbsp; [[Modulation_Methods/Objectives_of_Modulation_and_Demodulation|Objectives of modulation and demodulation]].
 *Particular reference is made to the page &nbsp;[[Modulation_Methods/Objectives_of_Modulation_and_Demodulation#Channel_bundling_.E2.80.93_Frequency_Division_Multiplexing|Channel bundling &ndash; Frequency Division Multiplexing]].

@@ Line 52: / Line 52: @@
 </quiz>
-===Model solution===
+===Solution===
 {{ML-Kopf}}
 '''(1)'''&nbsp; <u>Answer 1</u> is correct.

@@ Line 55: / Line 55: @@
 {{ML-Kopf}}
 '''(1)'''&nbsp; <u>Answer 1</u> is correct.
-*'''FDM'''&nbsp; (''Frequency Division Multiplexing'').
+*'''FDM'''&nbsp; ("Frequency Division Multiplexing").
-*The alternative multiplexing method, &nbsp; '''TDM'''&nbsp; (''Time Division Multiplexing'') can only be implemented with a digital communications system.
+*The alternative multiplexing method, &nbsp; '''TDM'''&nbsp; ("Time Division Multiplexing")&nbsp; can only be implemented with a digital communications system.
-'''(2)'''&nbsp; From the total bandwidth&nbsp; $\text{20.5 MHz}$ and the channel bandwidth&nbsp; $\text{0.3 MHz}$&nbsp; we get $\underline{K = 68}$.
+'''(2)'''&nbsp; From the total bandwidth&nbsp; $\text{20.5 MHz}$&nbsp; and the channel bandwidth&nbsp; $\text{0.3 MHz}$&nbsp; we get $\underline{K = 68}$.
 '''(3)'''&nbsp; <u>Answers 1 und 4</u> are correct:
-*The channel spacing and thus the bandwidth 300 kHz $\text{300 kHz}$&nbsp; available for a channel is significantly larger in the VHF range than for long, medium and short wave broadcasting. Although the frequency modulation used in FM broadcasting is characterized by better quality, it also requires more bandwidth.
+*The channel spacing and thus the bandwidth&nbsp; $\text{300 kHz}$&nbsp; available for a channel is significantly larger in the VHF range than for long, medium and short wave broadcasting.&nbsp; Although the frequency modulation used in FM broadcasting is characterized by better quality,&nbsp; it also requires more bandwidth.
-*For comparison, in the medium wave range, amplitude modulation and a channel spacing of &nbsp; $\text{9 kHz}$&nbsp; is always used (in Europe). The AF bandwidth is $\text{4.5 kHz}$.
+*For comparison,&nbsp; in the medium wave range,&nbsp; amplitude modulation and a channel spacing of&nbsp; $\text{9 kHz}$&nbsp; is always used&nbsp; (in Europe) &nbsp; <br>&rArr; &nbsp; the source signal bandwidth is&nbsp; $B_{\rm LF} = \text{9 kHz/2 = 4.5 kHz}$.
-*The range of VHF is smaller than in the other frequency ranges because VHF radio waves are not reflected by the ionosphere.  Therefore, a VHF transmission network usually consists of quite a large number of transmitters, which are set up at small distances from each other – and mostly at an elevation. &nbsp; &rArr; &nbsp; Answer 2 is incorrect.
+*The range of VHF is smaller than in the other frequency ranges because VHF radio waves are not reflected by the ionosphere.&nbsp;  Therefore,&nbsp; a VHF transmission network usually consists of quite a large number of transmitters,&nbsp; which are set up at small distances from each other – and mostly at an elevation &nbsp; &rArr; &nbsp; answer 2 is incorrect.
-*The signal arriving at the receiver has a much lower level than the transmission signal $s(t)$ &nbsp;, due to atmospheric attenuation, which increases at least quadratically with distance.&nbsp;  &rArr; &nbsp; Answer 3 is incorrect.
+*The signal arriving at the receiver has a much lower level than the transmission signal $s(t)$,&nbsp; due to atmospheric attenuation,&nbsp; which increases at least quadratically with distance&nbsp;  &rArr; &nbsp; answer 3 is incorrect.
-*In a radio receiver, the tuner indeed has the task of channel separation. &nbsp; &rArr; &nbsp; Answer 4 is correct.
+*In a radio receiver, the tuner indeed has the task of channel separation &nbsp; &rArr; &nbsp; answer 4 is correct.
 {{ML-Fuß}}

@@ Line 6: / Line 6: @@
 Electromagnetic waves in a frequency range from&nbsp; $\rm 30$&nbsp; to&nbsp; $\text{300 MHz}$&nbsp; – corresponding to wavelengths between one and ten meters – are referred to as&nbsp; "ultra-short waves".
-In common parlance, USW is also understood to mean the VHF II&nbsp; ("Very High Frequency")&nbsp; band, from&nbsp; $\text{87.5}$&nbsp; to&nbsp; $\text{108 MHz}$,&nbsp; which is still primarily used in Central Europe today for transmitting frequency-modulated radio programs using analog technology.
+In common parlance, USW is also understood to mean the VHF II&nbsp; ("Very High Frequency")&nbsp; band, from&nbsp;  $\text{87.5}$&nbsp; to&nbsp; $\text{108 MHz}$,&nbsp; which is still primarily used in Central Europe today for transmitting frequency-modulated radio programs using analog technology.
 The entire frequency band is divided into several channels,&nbsp; each with a channel spacing of &nbsp; $\text{300 kHz}$.
 The diagram displays the principle as a flow chart:
-*A total of &nbsp;$K$&nbsp; signals &nbsp;$q_k(t)$&nbsp; with different carrier frequencies &nbsp;$f_1$, &nbsp;$f_2$,  ... , &nbsp;$f_K$&nbsp; are modulated and added together.
+*A total of &nbsp;$K$&nbsp; signals &nbsp;$q_k(t)$&nbsp; with different carrier frequencies &nbsp;$f_1$,&nbsp;$f_2$,  ... ,&nbsp;$f_k$,  ... , &nbsp;$f_K$&nbsp; are modulated and added together.
 *The summed signal is then beamed from a transmitter after power amplification.&nbsp;
 *This outgoing signal is referred to as the transmission signal &nbsp;$s(t)$.
@@ Line 24: / Line 24: @@
 ''Hints:''
 *This exercise belongs to the chapter &nbsp; [[Modulation_Methods/Zielsetzung_von_Modulation_und_Demodulation|Objectives of modulation and demodulation]].
-*Particular reference is made to  &nbsp;[[Modulation_Methods/Zielsetzung_von_Modulation_und_Demodulation#B.C3.BCndelung_von_Kan.C3.A4len_.E2.80.93_Frequenzmultiplex|Channel bundling &ndash; frequency division multiplexing]].
+*Particular reference is made to the page &nbsp;[[Modulation_Methods/Zielsetzung_von_Modulation_und_Demodulation#B.C3.BCndelung_von_Kan.C3.A4len_.E2.80.93_Frequenzmultiplex|Channel bundling &ndash; frequency division multiplexing]].
@@ Line 34: / Line 34: @@
 {Which multiplexing method is used here?
 |type="()"}
-+ Frequency Division multiplexing.
++ Frequency Division Multiplexing.
-- Time Division multiplexing.
+- Time Division Multiplexing.
 {What is the maximum number of programs that could be transmitted in the VHF II band?
@@ Line 46: / Line 46: @@
 - The range of FM radio waves is greater than that of long-wave, medium-wave and short-wave broadcasting.
 - The signal arriving at the receiver &nbsp;$r(t)$&nbsp; is almost indistinguishable from the transmission signal  &nbsp;$s(t)$.
-+ The functional unit of a radio receiver for channel separation ("setting the radio station") is the tuner.
++ The functional unit of a radio receiver for channel separation&nbsp; ("setting the radio station")&nbsp; is the&nbsp; "tuner".
 <br><br>

← Older revision	Revision as of 10:24, 1 November 2021
(No difference)

@@ Line 4: / Line 4: @@
 [[File:P_ID939__Mod_Z_1_1.png|right|frame|Model of an FM radio transmitter]]
-Electromagnetic waves in a frequency range from &nbsp; $\rm 30$&nbsp; to&nbsp; $\text{300 MHz}$&nbsp; – corresponding to wavelengths between one and ten metres – are referred to as ultra-short wave (USW).
+Electromagnetic waves in a frequency range from&nbsp; $\rm 30$&nbsp; to&nbsp; $\text{300 MHz}$&nbsp; – corresponding to wavelengths between one and ten meters – are referred to as&nbsp; "ultra-short waves".
-In common parlance, USW is also understood to mean the VHF II&nbsp; (''Very High Frequency'')&nbsp; band, from&nbsp; $\text{87.5}$&nbsp; to&nbsp; $\text{108 MHz}$&nbsp;, which is still primarily used in Central Europe today for transmitting frequency-modulated radio programs using analog technology.
+In common parlance, USW is also understood to mean the VHF II&nbsp; ("Very High Frequency")&nbsp; band, from&nbsp; $\text{87.5}$&nbsp; to&nbsp; $\text{108 MHz}$,&nbsp; which is still primarily used in Central Europe today for transmitting frequency-modulated radio programs using analog technology.
-The entire frequency band is divided into several channels, each with a channel spacing of &nbsp; $\text{300 kHz}$.
+The entire frequency band is divided into several channels,&nbsp; each with a channel spacing of &nbsp; $\text{300 kHz}$.
 The diagram displays the principle as a flow chart: