I shook hands with her. "Hello, Miss Asakuma."
"Theresa."
"Okay."
"Isn't she beautiful?" Sanders said, acting as if he took credit for it. "Just beautiful."
"Yes," I said. "Actually, I'm surprised you're not a model."
There was an awkward moment. I couldn't tell why. She turned quickly away.
"It never interested me," she said.
And Sanders immediately jumped in and said, "Theresa, Lieutenant Smith needs us to copy some tapes. Thesetapes."
Sanders held one out to her. She took it in her left hand and held it to the light. Her right hand remained bent at the elbow, pressed to her waist. Then I saw that her right arm was withered, ending in a fleshy stump protruding beyond the sleeve of her jeans jacket. It looked like the arm of a Thalidomide baby.
"Quite interesting," she said, squinting at the tape. "Eight-millimeter high density. Maybe it's the proprietary digital format we've been hearing about. The one that includes real-time image enhancement."
"I'm sorry, I don't know," I said. I was feeling foolish for having said anything about being a model. I dug into my box and brought out the playback machine.
Theresa immediately took a screwdriver and removed the top. She bent over the innards. I saw a green circuit board, a black motor, and three small crystal cylinders. "Yes. It's the new setup. Very slick. Dr. Sanders, look: they're doing it with just three heads. The board must generate component RGB, because over here – you think this is compression circuitry?"
"Probably digital to analog converter," Sanders said. "Very neat. So small." He turned to me, holding up the box. "You know how the Japanese can make things this way and we can't? They kaizen'em. A process of deliberate, patient, continual refinements. Each year the products get a little better, a little smaller, a little cheaper. Americans don't think that way. Americans are always looking for the quantum leap, the big advance forward. Americans try to hit a home run – to knock it out of the park – and then sit back. The Japanese just hit singles all day long, and they never sit back. So with something like this, you're looking at an expression of philosophy as much as anything."
He talked like this for a while, pivoting the cylinders, admiring it. Finally I said, "Can you copy the tapes?"
"Sure," Theresa said. "From the converter, we can run a signal out of this machine and lay it down on whatever media you like. You want three-quarter? Optical master? VHS?"
"VHS," I said.
"That's easy," she said.
"But will it be an accurate copy? The people at JPL said they couldn't guarantee the copy would be accurate."
"Oh, hell, JPL," Sanders said. "They just talk like that because they work for the government. We get things donehere. Right Theresa?"
But Theresa wasn't listening. I watched her plugging cables and wires, moving swiftly with her good hand, using her stump to stabilize and hold the box. Like many disabled people, her movements were so fluid it was hardly noticeable that her right hand was missing. Soon she had the small playback machine hooked to a second recorder, and several different monitors.
"What're all these?"
"To check the signal."
"You mean for playback?"
"No. The big monitor there will show the image. The others let me look at the signal characteristics, and the data map: how the image has been laid down on the tape."
I said, "You need to do that?"
"No. I just want to snoop. I'm curious about how they've set up this high-density format."
Sanders said to me, "What is the actual source material?"
"It's from an office security camera."
"And this tape is original?"
"I think so. Why?"
"Well, if it's original material we want to be extra careful with it," Sanders said. He was talking to Theresa, instructing her. "We don't want to set up any feedback loops scrambling the media surface. Or signal leaks off the heads that will compromise the integrity of the data stream."
"Don't worry," she said. "I got it handled." She pointed to her setup. "See that? It'll warn of an impedance shift. And I'm monitoring the central processor too."
"Okay," Sanders said. He was beaming like a proud parent.
"How long will this take?" I said.
"Not long. We can lay down the signal at very high speed. The rate limit is a function of the playback device, and it seems to have a fast-forward scan. So, maybe two or three minutes per tape."
I glanced at my watch. "I have a ten-thirty appointment I can't be late for, and I don't want to leave these . . ."
"You need all of them done?"
"Actually, just five are critical."
"Then let's do those first."
We ran the first few seconds of each tape, one after another, looking for the five that came from the cameras on the forty-sixth floor. As each tape started, I saw the camera image on the central monitor of Theresa's table. On the side monitors, signal traces bounced and jiggled like an intensive care unit. I mentioned it.
"That's just about right," she said. "Intensive care for video." She ejected one tape, stuck in another, and started it up. "Oops. Did you say this material was original? It's not. These tapes are copies."
"How do you know?"
"Because we got a windup signature." Theresa bent over the equipment, staring at the signal traces, making fine adjustments with her knobs and dials.
"I think that's what you got, yes," Sanders said. He turned to me. "You see, with video it's difficult to detect a copy in the image itself. The older analog video shows some degradation in successive generations, but in a digital system like this, there is no difference at all. Each copy is literally identical to the master."
"Then how can you say the tapes are copies?"
"Theresa isn't looking at the picture," Sanders said. "She's looking at the signal. Even though we can't detect a copy from the image, sometimes we can determine the image came from another video playback, instead of a camera."
I shook my head. "How?"
Theresa said, "It has to do with how the signal is laid down in the first half-second of taping. If the recording video is started before the playback video, there is sometimes a slight fluctuation in the signal output as the playback machine starts up. It's a mechanical function: the playback motors can't get up to speed instantaneously. There are electronic circuits in the playback machine to minimize the effect, but there's always an interval of getting up to speed."
"And that's what you detected?"
She nodded. "It's called a windup signature."
Sanders said, "And that never happens if the signal is coming direct from a camera, because a camera has no moving parts. A camera is instantaneously up to speed at all times."
I frowned. "So these tapes are copies."
"Is that bad?" Sanders said.
"I don't know. If they were copied, they might also be changed, right?"
"In theory, yes," Sanders said. "In practice, we'd have to look carefully. And it would be very hard to know for certain. These tapes come from a Japanese company?"
"Yes."
"Nakamoto?"
I nodded. "Yes."
"Frankly I'm not surprised they gave you copies," Sanders said. "The Japanese are extremely cautious. They're not very trusting of outsiders. And Japanese corporations in America feel the way we would feel doing business in Nigeria: they think they're surrounded by savages."