Ring modulation

The single-electron reduction and oxidation of Co(salen) is solvent dependent as a result of the available coordination sites perpendicular to the CoN202 plane.1220 Furthermore, substituents on the phenyl rings modulate the observed redox potentials and subsequently the 02 binding constants. Hammett correlations are obtained.1221 Potentiometric titrations were performed to determine the 02 binding constants and species distribution as a function of pH for a variety of Schiff base Co complexes.1222... 

As well as a linear string of ring modules, one can also create a branched string of rings, as illustrated in Figure 4. IUPAC names this catenane as [4]- [cycloeicosane]-2-[cyclodotriacontane-2i-cycloeicosane]-... 

Alternatively, the second of these two modules can be left out, as in 122 and 123 (Figure 9.27). Here, the lactam module and the lipophilic ring module on the other end are connected by a flexible alkyl linker, leading to structures that are reminiscent to those constructed by fragment-based approaches, thus forming a third inhibitor subfamily (Figure 9.27). 

Ring modulation and synchronization go beyond this to create interactive effects, in which a parameter controlling one voice also affects the sound produced by a second voice. In both cases, the special effect is created by a difference in the frequencies (pitches) of the two voices. 

Ring modulation is a special type of synchronization in which overtones almost completely suppress the original tones. What you re left with is a sound composed chiefly of nonharmonic overtones. The results are often surprising and bear little if any resemblance to so-called natural sounds. 

Used with care, ring modulation can produce haunting, beautiful effects. However, it works through a complex interaction of two waveforms, largely suppressing what you d hear without the feature. So it can be difficult to handle if you don t know how it works in the first place. 

To switch on synchronization, press the f7 function key. The f5 key switches on ring modulation, and the f3 key activates both effects at once. 

When synchronization is selected, you ll hear the beating effect as the tone ascends in pitch and the two voices move in and out of phase with each other. Ring modulation creates a rich, spacey sound. Note that you can pause the tone with CONTROL while pressing a function key. As you ll hear, the sounds are far less exciting when both frequencies remain... 

In both synchronization and ring modulation, it is the frequency of the program voice which affects the carrier voice. The other program voice parameters have no effect on the carrier (of course, they will affect the program voice if it is turned on). 

As you ll discover by experimenting, these special effects work well with certain combinations, and poorly (or not at all) with others. Ring modulation works only when you set the carrier voice to the triangle waveform. Synchronization works with any waveform, but synchronizing any frequency with the noise waveform (a nearly random combination of many frequencies) doesn t accomplish much. The sawtooth and pulse waves often sound similar. 

Ring modulation and synchronization are most pronounced when the program frequency is considerably lower than the carrier frequency and remains fixed, as in the above examples. Changing the program frequency to a higher fixed value makes the two voices move in and out of phase more... 

You can use ring modulation or synchronization with any of the 128 s three voices, but the voice relationships are fixed voice 1 modulates voice 2, voice 2 modulates voice 3, and voice 3 modulates voice 1. 

To select these special effects in BASIC, simply add 2, 4, or 6 to the normal POKE value for the waveform register of the voice you want to affect. For instance, POKE 54276,17 selects the triangle waveform for voice 1. POKE 54276,19 adds synchronization to the triangle wave (17+2 = 19). POKE 54276,21 enables a ring-modulated triangle wave and POKE 54276,23 turns on both effects at once. Use POKE 54276,67 to select synchronization with the pulse waveform, and so forth. 

Naturally, you can use these effects with more than one voice at a time. If you select synchronization in voices 1 and 3, then voice 1 will be affected by voice 3 s frequency, and voice 3 will be affected by voice 2 s frequency. However, because multivoice modulation creates so many overtones, it s easy for things to get out of hand. If you create a three-note musical chord with triangle waves in every voice, and then switch each to ring modulation, the result will be anything but musical. 

Figure 9 Schematic ring module Figure 10 Prototype module...

Halawani D, Leblanc A, Rouiller I et al. (2009) Hereditary inclusion body myopathy-linked p97/VCP mutations in the NH2-domain and the D1 ring modulate p97/VCP ATPase activity and D2 AAA -I- ring conformation. Mol Cell Biol 29( 16), 4484-4494. 

There are two variants of amplitude modulation classic amplitude modulation (AM) and ring modulation (RM). 

Ring modulation may also be achieved by the multiplication of two signals (Figure 2.6). The multiplication of two sounds results in a spectrum containing frequencies that are the sum... 

Lobe envelopes, however, have their own unwanted side-effects. Note that the amplitude of the whole signal now rises and falls periodically. This is a clear case of ring modulation (see Chapter 2) in which the windowing frequency acts as the modulating frequency. Enveloped windowing also may distort the analysis process, but the result is still more accurate than with windowing without envelopes. 

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