Re: Love/Hate
It was videotape, not audio cassette tape.
32 publicly visible posts • joined 13 Mar 2013
The Texas Instruments chips had 64Kbit dies inside but the packaged chips were labelled as 32Kbit parts and sold as such. The part number indicated which half was good. All 8 of them in any one machine had to have the same good half. There was provision on the plug-in daughterboard in early versions or on the later single PCBs to select which type was fitted.
Blu-Ray does not use lossless compression. For example the uncompressed rate of 1920x1080x25 interlaced 8 bit luminance is 51.84 Mbyte/s. Add on the same again for the two colour differences each 2:1 subsampled and you are over 103 Mbyte/s. That is 825 Mbit/s. Far in excess of 20-30 Mbit/s.
It may come close to "visually lossless" but what comes out of the decoder is not exactly the same as what went into the encoder. But pretty good going when you consider the compression ratio.
Service manuals were prepared for use by service departments, not end-users. But the economics of mass production versus the cost of skilled repair technicians means it is now cheaper to give the customer a new replacement that run a service department that actually repairs things. Similarly for out of warranty items - a new item can often be purchased for less than what a service department would need to charge to cover its running costs. Hence service departments that actually repair things disappear, and the need for service manuals (which if any good are expensive to produce) disappear too.
Sony's early PAL TVs used the modulated chrominance signal from only every alternate (in time) line. The gaps were filled by repetition using a glass delay line so that the following demodulation stages saw a signal with no line by line inversion of the phase of the V component. In effect the PAL signal was converted into an NTSC like signal.
My parents' first TV was a Decca DM4C 17 inch purchased in the late 1950s. (I remember seeing the very first episode of Coronation Street on it.) One Easter my father decided to take it with us when we went to spend the break with my grandparents some 60 miles away who did not have a TV. No picture could be obtained. Sound was OK but not a hint of anything lighting up the screen.
Back home and with a still dead screen the local TV repairman was called in. Back in those days the electron gun was deliberately angled such that it did not fire directly along the axis of the tube. An "ion trap" thing was clamped round the neck near the heater. Shaped like an omega clip, two curved pieces of metal with a permanent magnet between one pair of their ends and a nut and bolt at the other ends. Adjusted in the factory to bend the electron beam so that it went through the centre of the deflection coils but the heavier ions did not. With the hour and a half of vibration during the car journey the thing had become loose and the weight of the magnet had tuned the assembly sufficiently out of position that no electrons at all were getting forward to the deflection coil area and thence to the phosphor screen.
There are several capacitors between the instantaneously changing power draw circuity and the battery. Those smooth out the rapid variations in power draw. Furthermore the OS is not sitting doing nothing - lots of things are happening in the background making their own changes to the current consumption. Those are merged with any changes from the character drawing circuitry and the resultant total variation smoothed by the capacitors.
I very much doubt that any measuring device in the battery could tell what characters are being typed.
"It's supposed to indicate that it's supplementary to normal Over The Air (OTA) broadcast."
Wrong!
As Wikipedia says:
"In broadcasting, over-the-top content (OTT) refers to delivery of audio, video, and other media over the Internet without the involvement of a multiple-system operator in the control or distribution of the content."
The article incorrectly states that the first 1000 or so microdrives had EPROMs. They only had one IC in them and it wasn't a ROM or EPROM. The Interface 1 had a ROM (8 Kbyte?) and I have previously heard that early units had EPROMs rather than masked ROMs.
The chip with the armadillo heatsink was the Sinclair Super IC12 power amp. It was actually a remarked Texas Instruments device. I soldered all 5 of mine into matching PCBs also supplied by Sinclair. I cannot recall if the PCBs were an extra purchase or bundled with the chip.
The earlier IC10 audio power amp, with metal heatsink bar running through it, was a rebadged Plessey device.