HW 9: Modulation Synthesis & History of Analog Synthesizers

In classic amplitude modulation, the amplitude of a bipolar sine wave is modulated by a bipolar sine wave.

false

In amplitude/ring modulation, what happens when the carrier has a spectrum with more than one partial in it?

A) The effects of modulation are applied to the lowest partial in the carrier spectrum.

B) The effects of modulation are applied to every partial in the carrier spectrum.

C) The result is the same as a sinusoidal carrier: exactly two new sidebands are produced.

D) The effects of modulation are applied to the highest partial in the carrier spectrum.

B

Which of the following statements about phase modulation and frequency modulation is true?

A) PM sounds different than FM, but involves the same implementation.

B) PM involves a different implementation than FM, and sounds completely different.

C) PM involves a different implementation than FM, but sounds indistinguishable.

D) PM and FM are completely identical processes.

E) FM can be done with any wave shape, but PM can only be done with sine waves.

C

Consider the following example of modulation synthesis:

 

- amplitude modulation
- carrier frequency = 100 Hz
- modulator frequency = 190 Hz

What frequencies are present in the output spectrum?

A) [10, 90, 100, 190, 200, 290] Hz

B) [90, 290] Hz

C) [90, 100, 290] Hz

D) [10, 190] Hz

E) [10, 100, 190] Hz

C

Consider the following example of modulation synthesis:

 

- ring modulation
- carrier frequency = 2 kHz
- modulator frequency = 40 Hz

 

What frequencies are present in the output spectrum?

A) 1960, 2040] Hz

B) [38, 42] Hz

C) [1960, 2000, 2040] Hz

D) [1940, 2060] Hz

E) [1940, 2000, 2060] Hz

F) [38, 40, 42] Hz

A

Consider the following example of modulation synthesis:

 

- frequency modulation
- carrier frequency = 600 Hz
- modulator frequency = 240 Hz
- index of modulation = 2

How many significant sideband pairs appear in the output spectrum?

3

Consider the following example of modulation synthesis:

 

- frequency modulation

- carrier frequency = 600 Hz

- modulator frequency = 240 Hz

- index of modulation = 2

 

What is the modulator deviation, in Hz?

480

Consider the following example of modulation synthesis: 

 

- frequency modulation

- carrier frequency = 600 Hz

- modulator frequency = 240 Hz

- index of modulation = 2 

 

What is the FM bandwidth, in Hz?

1440

Consider the following example of modulation synthesis:

 

- frequency modulation
- carrier frequency = 600 Hz
- modulator frequency = 240 Hz
- index of modulation = 2

Considering significant sideband pairs only, which answer best represents the frequencies that will be present in the output spectrum?

A) [120, 360, 600, 840, 1080, 1320, 1560] Hz

B) [120, 360, 600, 840, 1080] Hz

C) [120, 360, 600, 840, 1080, 1320] Hz

D) [600] Hz

E) [360, 600, 840] Hz

C

Consider the following example of modulation synthesis:

 

- frequency modulation
- carrier frequency = 600 Hz
- modulator frequency = 240 Hz
- index of modulation = 2

 

Is this a harmonic spectrum? If so, what is the fundamental frequency?

A) Yes, 600 Hz

B) Yes, 240 Hz

C) Yes, 20 Hz

D) Yes, 120 Hz

E) No, it is inharmonic

F) Yes, 360 Hz

D

What does it mean for an analog synthesizer to be modular?

A) It is an entirely analog device, with no digital capabilities.

B) It is capable of polyphony.

C) It consists of individual synthesis units called "modules" that can be arbitrarily connected to each other.

D) It can communicate with other synthesizers via MIDI.

E) It is capable of modulation synthesis.

F) It is capable of arpeggiating any musical scale mode (e.g. ionian, dorian, phrygian)

C

During the analog synthesizer era, the vacuum tube replaced the transistor as the primary means of controlling and amplifying audio signals.

false

What was the control mechanism for the very first synthesizer designed and built by Don Buchla for the San Francisco Tape Music Center?

A) A device that tracked the motion of the user's eyes.

B) A device that used a grounded capacitor and the Heterodyne principle, similar to a theremin.

C) A three-track Ampex tape deck that captured synthesizer control data and recorded it onto magnetic tape.

D) An optical device that analyzed hand shape to control waveform spectrum.

E) A device that received MIDI messages from a remote computer.

D

In the 1970s, “hybrid” synthesizers began to appear, characterized by analog audio signals whose configurations were digitally programmable and controllable.

true

Wendy Carlos’ 1968 album, Switched-On Bach, is considered to have been partly responsible for the breakthrough commercial success of which line of synthesizers?

A) Moog

B) Yamaha

C) EMS Ltd.

D) Buchla

E) Sequential Circuits

A

The Buchla 200 Series synthesizers were MIDI-compliant.

false

The Yamaha DX7 was one of the first MIDI-compliant synthesizers.

true

The Oberheim Four Voice was the first commercially successful polyphonic synthesizer.

true

Who was NOT a primary user or developer of the GROOVE system developed at Bell Labs?

A) Laurie Spiegel

B) Max Mathews

C) Emmanuel Ghent

D) F. Richard Moore

E) Don Buchla

E

Musical tuning was a significant challenge with analog synthesizer technology, because synthesizer's electrical components were susceptible to environmental temperature changes.

true