Key words: "CONNECTED TO THE INPUT". In a receiver, an RF amplifier is generally used to amplify the tiny signal (i.e., microvolts) arriving from the Antenna. Once amplified, the incoming signal is fed to the Mixer.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In a receiver, an RF amplifier is generally used to amplify the tiny signal (i.e., microvolts) arriving from the Antenna. Once amplified, the incoming signal is fed to the Mixer.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The Mixer in a receiver takes in the incoming signal and mixes it with a local oscillator to transpose (usually down) the incoming signal to a fixed Intermediate Frequency (the Superheterodyne concept). Using a fixed and lower Intermediate Frequency regardless of operating frequency facilitates the achievement of high gain and selectivity.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The Mixer in a receiver takes in the incoming signal and mixes it with a local oscillator to transpose (usually down) the incoming signal to a fixed Intermediate Frequency (the Superheterodyne concept). Using a fixed and lower Intermediate Frequency regardless of operating frequency facilitates the achievement of high gain and selectivity.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The Mixer accepts two inputs: the incoming signal and the local oscillator. Mixing returns two new products: the sum of the two inputs, the difference of the two inputs. The IF Filter seeks to let only one of the products into the Intermediate Frequency chain for amplification through the IF Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The Mixer accepts two inputs: the incoming signal and the local oscillator. Mixing returns two new products: the sum of the two inputs, the difference of the two inputs. The IF Filter seeks to let only one of the products into the Intermediate Frequency chain for amplification through the IF Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Detection (recovery of the original message) in a Frequency Modulation receiver is performed by the 'Discriminator'. The Discriminator translates frequency deviation back to audio. Early discriminators were sensitive to amplitude variations and needed to be preceded by a 'Limiter' to remove amplitude variations from the received signal. Limiters are integral part of an FM system as they cut down the influence of noise.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Detection (recovery of the original message) in a Frequency Modulation receiver is performed by the 'Discriminator'. The Discriminator translates frequency deviation back to audio. Early discriminators were sensitive to amplitude variations and needed to be preceded by a 'Limiter' to remove amplitude variations from the received signal. Limiters are integral part of an FM system as they cut down the influence of noise.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Most receivers rely on an Audio Amplifier to provide sufficient volume from the loudspeaker.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

key words: "CONNECTS TO". The expected answer relies on the general concept of connecting something to a source: a hose to a tap, a house to the electrical grid or gas mains. In that sense, the loudspeaker CONNECTS to the Audio Amplifier. The Audio Amplifier connects to the Discriminator.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In a receiver, an RF amplifier is generally used to amplify the tiny signal (i.e., microvolts) arriving from the Antenna. Once amplified, the incoming signal is fed to the Mixer.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The mixer accepts two inputs: the incoming signal and the local oscillator. Mixing returns two new products: the sum of the two inputs, the difference of the two inputs. The IF Filter seeks to let only one of the products into the Intermediate Frequency chain for amplification through the IF Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The mixer accepts two inputs: the incoming signal and the local oscillator. Mixing returns two new products: the sum of the two inputs, the difference of the two inputs. The IF Filter seeks to let only one of the products into the Intermediate Frequency chain for amplification through the IF Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The mixer accepts two inputs: the incoming signal and the local oscillator. Mixing returns two new products: the sum of the two inputs, the difference of the two inputs. The IF Filter seeks to let only one of the products into the Intermediate Frequency chain for amplification through the IF Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The mixer accepts two inputs: the incoming signal and the local oscillator. Mixing returns two new products: the sum of the two inputs, the difference of the two inputs. The IF Filter seeks to let only one of the products into the Intermediate Frequency chain for amplification through the IF Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The mixer accepts two inputs: the incoming signal and the local oscillator. Mixing returns two new products: the sum of the two inputs, the difference of the two inputs. The IF Filter seeks to let only one of the products into the Intermediate Frequency chain for amplification through the IF Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an SSB/CW receiver, detection (recovery of the message) is performed by a 'Product Detector'. The 'Product Detector' mixes the Intermediate Frequency signal with a Beat Frequency Oscillator to transpose the IF signal down to the audible range. The demodulated signal is applied to an Audio Amplifier to provide sufficient drive for the loudspeaker.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an SSB/CW receiver, detection (recovery of the message) is performed by a 'Product Detector'. The 'Product Detector' mixes the Intermediate Frequency signal with a Beat Frequency Oscillator to transpose the IF signal down to the audible range. The demodulated signal is applied to an Audio Amplifier to provide sufficient drive for the loudspeaker.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an SSB/CW receiver, detection (recovery of the message) is performed by a 'Product Detector'. The 'Product Detector' mixes the Intermediate Frequency signal with a Beat Frequency Oscillator to transpose the IF signal down to the audible range. The demodulated signal is applied to an Audio Amplifier to provide sufficient drive for the loudspeaker.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an SSB/CW receiver, detection (recovery of the message) is performed by a 'Product Detector'. The 'Product Detector' mixes the Intermediate Frequency signal with a Beat Frequency Oscillator to transpose the IF signal down to the audible range. The demodulated signal is applied to an Audio Amplifier to provide sufficient drive for the loudspeaker.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In order of bandwidth requirements: CW = about 100 Hz, RTTY = about 600 Hz, SSB = 2 to 3 kHz, FM = 10 to 20 kHz.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

A measurement of the 'Signal + Noise' to 'Noise' ratio shows how well an incoming signal overcomes the inherent internal noise of a receiver. A sensitive receiver will render more signal and little remaining noise (less background noise on the reproduced signal) when compared to the base noise in the receiver. Measuring how strong a signal is required to produce a given 'S+N/N' ratio permits comparing receiver sensitivities.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

key words: LESS SENSITIVE. A sensitive receiver will render more signal and little remaining noise (less background noise on the reproduced signal) when compared to the base noise in the receiver. The better receiver can render weak signals with little noise.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In SSB, the FREQUENCY of the original modulating signal is conveyed by the POSITION of each side frequency within the sideband in relation to the phantom carrier (it has been suppressed). A sideband (a group of ever changing side frequencies) is formed by the sum (Upper Sideband) or difference (Lower Sideband) of the modulating frequencies and the carrier frequency. The original frequency can only be reproduced correctly by "re-inserting" a reference signal, the Beat Frequency Oscillator, and mixing it with the received signal. 'Beat' is synonym of mixing.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In SSB, the FREQUENCY of the original modulating signal is conveyed by the POSITION of each side frequency within the sideband in relation to the phantom carrier (it has been suppressed). A sideband (a group of ever changing side frequencies) is formed by the sum (Upper Sideband) or difference (Lower Sideband) of the modulating frequencies and the carrier frequency. The original frequency can only be reproduced correctly by "re-inserting" a reference signal, the Beat Frequency Oscillator, and mixing it with the received signal. 'Beat' is synonym of mixing.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The mixer accepts two inputs: the incoming signal and the local oscillator. Mixing returns two new products: the sum of the two inputs, the difference of the two inputs. The IF Filter seeks to let only one of the products into the Intermediate Frequency chain for amplification through the IF Amplifier. In this example, 3995 kHz minus 3540 kHz yields 455 kHz.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The problem presented here is an offending signal within the receiver passband (the range of frequencies allowed though the Intermediate Frequency chain). A 'Notch Filter' which attenuates a very narrow range of frequencies can be used to remove the interfering carrier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Three times letter S: Sensitivity, Selectivity and Stability. Sensitivity: render weak signals with less noise. Selectivity: the ability to separate signals from adjacent ones. Stability: staying on frequency over time despite temperature or voltage variations.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In order of bandwidth requirements: CW = about 100 Hz, RTTY = about 600 Hz, SSB = 2 to 3 kHz, FM = 10 to 20 kHz. A 2.4 kHz filter is just wide enough to accept an SSB signal. Wider a filter, lets in more noise. Too narrow a filter causes distortion.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In order of bandwidth requirements: CW = about 100 Hz, RTTY = about 600 Hz, SSB = 2 to 3 kHz, FM = 10 to 20 kHz. A 250 Hz filter is best to isolate a CW signal. Wider a filter, lets in more noise. Too narrow a filter causes distortion.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

key words: AUDIO STAGES. After the 'Product Detector', an incoming CW signal is now an audible tone. Most receivers render CW as a note somewhere in the range of 750 Hz to 850 Hz. Additional band-pass filtering (allowing only a certain range of frequencies) can be useful to knock down adjacent stations finding their way into the receiver passband (the range of frequencies allowed though the Intermediate Frequency chain) and producing higher or lower notes, say at 250 or 1000 Hz.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The 'Capture Effect' is specific to FM receivers: only the stronger of two signals at or near the same frequency will be demodulated. The complete suppression of the weaker signal occurs at the receiver limiter. When both signals are nearly equal in strength, or are fading independently, the receiver may switch from one to the other. http://en.wikipedia.org/

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none