OAL Special Seminar with Stan Ehrlich ------------------------------------- November 5, 2008 Ken Foote: Well, it's a pleasure to welcome Stan Ehrlich to the Woods Hole Oceanographic Institution - department of Applied Ocean Physics and Engineering. We do have a series of, for us,... Foote: We know something of Stan's personal history. I've learned more today - I certainly have the facts in order - and I'd like to briefly review some of those with you. We are touched in many ways and it will be clear when I start to mention this just what those connections are. Stan has two degrees from Brown University. The first is a Bachelor's, 1944, in mechanical engineering, but he met Bruce Lindsay as a sophomore, which... Stan Ehrlich: No, as a freshman. Foote: ...freshman, which... Ehrlich: In 1941. Foote: ...was transformative. And his second degree, a Master's, was taken in Physics in 1945. You then went to MIT for several years to do additional postgraduate work, then went to the U.S. Navy Underwater Sound Laboratory in New London, Connecticut from 1948 to '53. Then Raytheon Company which became your home for the next 40 years. Stan rose from the rank of Senior Engineer to Consulting Engineer with was the highest technical staff position at Raytheon Company. You would have to become a manager to exceed that, but Stan was comfortable at the highest technical rank at Raytheon Company. Ehrlich: Oh, that was higher than many management ranks, actually. Foote: We appreciate that. Ehrlich: Yeah. Foote: He has been a member of the Acoustical Society of America since 1948, if memory is correct. Ehrlich: Yeah. I joined as soon as I had enough money to join. [*Everyone laughs*] Ehrlich: I didn't have any money before that. Foote: He served as President of the Society after the typically long gestation period as Vice President Elect, Vice President, President Elect, with a mandatory gap in between to space things out. That was 1996 to 1997, so almost within the last 10 years you served as President of the Society. Stan was Associate Editor for the Journal of the Acoustical Society of America for 21 years in transduction. By then he had exceeded the 3 term limit by 4 terms, but identified his successor, [?Alan Zucker?], who, like Stan, is a silver medalist of the Acoustical Society of America. So there's much distinction here. At the same time - during the same period - Stan served as Editor-in-Chief of the IEEE Journal of Oceanic Engineering - 1981 to '87. We have one of his successors here with us [*Foote motions towards Jim Lynch, who nods his head*] and it's a very strong-going concern but only because of the work of our Editors-in-Chief. Ehrlich: The Journal was just about to fold and they asked me if I would take it over and I brought it back to life, actually, and it's still going strong. Foote: That was a major resuscitation. Ehrlich: Yeah, it was. Foote: Today I view it as a gold mine for technology in the whole oceanic engineering area not just underwater sound, but a very important reference source for people working in this area. Stan founded a chapter in acoustics for the ASA. He's received a number of awards in addition to the silver medal of the Society he received the [?Meripol?] Gold Medal awarded by an Indian society and subsequently a silver medal in 2007 for work done to foster national collaboration. I met Stan in 1968 he taught underwater sound at Raytheon Company Submarine Signal Division and we have several alums here of "Sub Sig", which I understand you joined in 1960? Ehrlich: What? Foote: At Submarine Signal Division of Raytheon Company? Ehrlich: Yes. In 1960 we moved to Rhode Island. Foote: Following several years... Ehrlich: ...and we're still the Submarine Signal Division. Foote: Before that much of the sonar work was being done in Massachusetts. For instance, Boston, Waltham, Wayland, Newton, but eventually it was consolidated in Portsmouth, Rhode Island and Stan worked there for more than 30 years at that location. Ehrlich: 38 years with them. Foote: ...with Raytheon Company. In addition to doing some teaching of an influential character I believe Stan has a very special ability in approximation. As in: the art of approximation. We all know the story of Enrico Fermi measuring the first atomic blast [and] how much energy was actually expended by dropping paper balls out of his pocket [and] measuring the deflection from the blast wave, and he came within 10% of the yield. But all the years I knew Stan at the Submarine Signal Company he could do that. He knew his logarithms, and could do a lot even without a slide-rule, not to mention a digital computer. Barbara Ehrlich: I want to interrupt here, because he told me he memorized the log tables and interpolated in his head. [*Everybody laughs*] Foote: Well, that took care of multiplication and division. Tim Stanton: Yeah. Foote: So, we'd like to just ask you... Ehrlich: Well, I have an even older one, I got my picture in the paper in the Providence Journal back in 1930 when I was 5 years old and you [*Turns to Barbara Ehrlich*] I think you have the scrapbook from that now. Barbara Ehrlich: Steve does, yes. Ehrlich: What? Barbara Ehrlich: My brother does. Ehrlich: OK, but at any rate, what happened: when I was 5 years old, I was able to figure out - and that was 1930 - I was able to figure out the day of the week that any day during 1930 came. You know, like if you told me June 4, 1930 I would tell you what day of the week it was. So, and they wrote me up for that and I got a bunch of extra things copied around and every once in a while they even republish some of these things from way back then, but that doesn't happen too much anymore. But that was my first publication. [*Everybody laughs*] Jim Doutt: That's pretty impressive at 5 years old. Ehrlich: Well, it always surprises me now that I did, too. And I've found a formula for doing it so I can do it all the way back and forth over almost any number of years. You have to make a correction when they change the calendar from Julian to Gregorian back in 1752. Foote: A walking perpetual calendar calculator. [*Everyone laughs*] Ehrlich: Yes, exactly. Stanton: I guess I'd like to elaborate, too, on what Ken said. I started Raytheon - [*Points to Ehrlich*] well, you were already a Consulting Engineer - I was at that point the entry level, which was the Senior Engineer, but what was impressive was, with the first major project I was on involved designing arrays and developing the amplitude shading coefficients to based on a certain specification for beam width in side-lobe level and certainly we had the mainframe computer (batch mode) where you submit the card of - the whole stack of cards and everything - and it took a day to come back with syntax errors and so on. It took a whole week to get anything running, which was 5 attempts basically, but Stan did it his own way, without a computer, and I remember just how admired he was and respected by everyone there because they would ask him for a task and he would just give it back just something hand written with shading coefficients (I'm talking about an m by m array with certain specifications) and he figured it out (the coefficients) and we would just take it without question because they gave terrific results, but again it's along the line of having a deep intuitive feeling for things and being able to just do it on first principles and come very close to the optimum answer, if not hitting it. So anyway, while the rest of us were turning the crank on the unwieldy computing system at that point and taking weeks to get results. [*Laughs*] Foote: This is probably a good point to ask you about your work on super directivity. Ehrlich: OK. Well, I was trying to get a number of point arrays to form a beam without getting a lot of the noise involved, and super directivity is a way to cut out the noise. However, you start with a whole lot of noise and you have to figure out a way to cut that out first, and to be able to pick up a small signal in a fairly large amount of noise. And so you try to make the array, if the noise is fairly uniform, you try to do that by cutting out the noise from all directions except the one you are looking for. Up to a point you can do that, provided you don't get to high a side-lobe problem, because sometimes you get side-lobes that get too high and destroy the advantage of the array, which is what you are trying not to do. And the other thing with super directivity is you try to use some of the same principals to establish from what direction a noise is coming and you try to get the array to be directionally sensitive. And you can do that with either with a super directive array or, if the noise isn't too heavy, you can do it with just a two-coat - a sine and a cosine - and an omni-directional array. And that can be all be put onto one cylinder because you can have a plus or minus this way and rotate it 90 degrees and then have just an omni. And between the three of them you use the omni to blank out: you put a phase shift in the omni and you use the omni to blank out one part of the deal and so it picks up the two positive quadrants, that sort of thing, and you pick up from that which direction it's coming from. And it tends to work out pretty well and its been used in various large sizes for low-frequencies and small-sizes for high-frequencies so that you can cover about an octave or so at a time with these things and after a while it doesn't pay to cover very much because when the sound gets too high in frequency [?it doesn't?] come from too far, you don't need much. Foote: Was there an ambiguity? Ehrlich: A multi-mode. It was called a multi-mode array. And it was done with an omni-directional and a sine/cosine. Foote: But it could resolve the ambiguity in direction. Ehrlich: It could resolve the 180 degree ambiguity. The omni helps you to resolve the ambiguity by how it matches up with the sine and cosine. Doutt: So is this what's used in the [?Dive4 sonar?] buoys? Ehrlich: What? Doutt: The [?Dive4 sonar?] buoys? Is it that principle that's used. Ehrlich: OK, It's used somewhere else. Doutt: Well, that's a question, actually. Ehrlich: Oh, I don't know whether. Underwater was a question 'cause what submarines were trying to do is they're trying find out if someone was pinging on them and they were trying to find the direction the ping was coming from, in that case, so they could take some action. Doutt: Mmhmm. Ehrlich: Either to run away from it or to go and attack depending on what they were choosing to do. Foote: Oh, Stan? If you would like, we have a board here. Lynch: No, it's alright. Foote: OK, yeah. Ehrlich: I don't think - if somebody needs something on the board I'll put it on, but... Foote: OK. Now, you received several patents for this, is that right? Ehrlich: I received either only one or two patents... to receive for that. Yeah, yeah. Two I think. Foote: And did this result in a device that Raytheon manufactured? Ehrlich: This resulted in some manufacturing facility, because we manufactured some of these arrays, yes. Right, and we had a hook on the market for a while and then we got some competition. Foote: Yeah. I was curious about your possible involvement in development of parametric sonar at Raytheon Company. Ehrlich: In my involvement in the what of something? Foote: Of parametric sonar. Ehrlich: Parametric? Foote: Parametric sonar. I believe Walsh was helping to develop that. Lynch: Yeah, George Walsh. Ehrlich: Yeah, I didn't do too much of that. I didn't do too much of that. Foote: Yeah. Also, you were involved with development of magnetostrictive transducers? Ehrlich: Well, when I first joined the sound lab in 1948 they were working with [?Perminder?] magnetostrictive transducers. [?Perminder?] is an allow of iron - it's 49% iron, 49% cobalt, and 2% vanadium. And the reason the vanadium is there is to make it pliable or malleable. So, the iron and cobalt are there to provide the magnetostrictive capability, and both iron and cobalt are magnetostrictive. And what you wind up doing is you wind up learning about magnetic hysteresis and magnetic [?glucks?] and things of that sort. What you try to do is you try to pulverize the magnetostrictive material so instead of it being a [?squarlar?] it becomes a linear device about the remnant point to which you have it or about whatever the midpoint is that you drive it around you try to make it nearly linear just to keep the losses down and the heating down. And so it becomes piezomagnetic but it's not a naturally piezoelectric. There's no naturally piezomagnetic substance, like the piezoelectrics, for example. Piezoelectrics you'll find - Quartz and Rochelle salt, and things of that sort - have piezoelectric properties. But then, of course, you also find the magnetostrictive materials in the ferro-electric materials like barium titanate and other things of that sort. And other various titanates, and things like that, that exist. And what you do with them is you try to polarize them to make them effectively piezoelectric, you can do a better job with them actually, but you do a good job with the magnetostrictive ones, too. And I did work on another magnetostrictive material that... Allegheny Ludlum used to make the [?Perminder?] and both the sound lab in New London and Raytheon were working with it. Raytheon was manufacturing sonar systems with transducers using [?Perminder?], and while I was at the lab in New London Westinghouse came out with a material called [?Hyperco?] and its main advantage was that it was still magnetostrictive but it was only 35% cobalt, which was an expensive material, And the only trouble was that it did not have the kind of properties that [Perminder?] did. It wasn't a good substitute. It did work, but it didn't work well enough to be a replacement for [?Perminder?]. So, I had a lot of experience playing around with [?Perminder?] and... Tim Duda: Were you building... Ehrlich: ...did a lot of work with minor loops and things like that, as well as the major loops. Yeah, yeah. You had a question? Tim Duda: Yeah. I was going to ask you if you were building prototypes, or looking at the properties of the material itself to pass on to a prototype division, or were you actually building prototype sources, or even designing production type units? Ehrlich: I'm missing your question. Do you think maybe Ken can repeat it? Tim Duda: Were you purely doing the research on the material itself or building a prototype to pass on to a prototype source development aid, you know, division? Ehrlich: Wait, the [?Hyperco?]? Duda: Or were you building the prototypes? Ehrlich: Well, you just had to make a ring stack of it to test the material. Duda: Right, but did you do top to bottom, you know: materials, source, engineering, packaging, or production units or systems? Ehrlich: The only thing I did that I patented was the directional sensor. Duda: Yes. Ehrlich: The other things all had patents. Barbara Ehrlich: He wants to know if you were part of every aspect of the research to production or, which aspect were you part of? Ehrlich: Oh, I wasn't in the production of sonar systems I was in the engineering backup for the production when I was at Raytheon. And if there was a problem then we had to figure out how to get around it. Duda: OK. Ehrlich: ..in the production system. Duda: I see. OK. I don't know how these things are structured. Ehrlich: We were trying to keep the people in production out of trouble. [*Everybody laughs*] Ehrlich: I worked in transduction a lot, too, as opposed to the system as a whole and then after a while I was involved in the whole system. You could work your way through the system from the transducer all the way to the display. Someone in background: Right. Foote: There are some follow-ups to this, but before we leave transduction, most of us are using piezoelectric transducers. Ehrlich: Or sometimes you use [?piezoelectric?] polarized. Otherwise you've used barium titanate, don't you? [Foote and Lynch nod heads] Ehrlich: Yeah, barium titanate is ferroelectric, you say? Foote: Yeah, but do you... Ehrlich: But it's polarized to be piezoelectric. [*Foote nods head*] Foote: The magnetostrictive transducers are very robust. Ehrlich: Oh yeah. Foote: Do you see them as still having a future or potential applications? Maybe for deep sea work? Ehrlich: They are robust but they are expensive and they are also hard to manufacture, relatively. Relative to the others, where you can just... The ceramic transducers are a lot cheaper and a lot easier to fabricate. And cost is a major factor in most things that the government buys. Foote: But for, let us say, deep sea applications or applications in water with ice or you're working at the surface. It seems the magnetostrictive transducers are sufficiently robust. Ehrlich: They can handle the deep sea very nicely; and you have to work a little harder to get the ceramic transducers to take the [weight], because they can get crushed and things like that. They are not as strong, if you absolutely have to have it. But most things that are on board a ship don't do down that deep, even submarines don't go too deep because otherwise they crush too. Lynch: We're fond of putting sources at all sorts of great depths, Stan. Ehrlich: What? Lynch: I said, we're fond of putting sources at all sorts of great depths. So, we're some of the exceptions to the rule around here. Ehrlich: Oh, OK. Duda: Yeah. Foote: We are currently developing a vehicle that will go to the deepest part of the ocean. Ehrlich: Well, they have bathyspheres and things like that'll go down as deep as the ocean. Duda: Yep. Lynch: Yeah, but we're interested in putting sources on them. Duda: Yeah. Ehrlich: What? Lynch: We're interested in putting acoustics on them. Ehrlich: Yes. Duda: Or positioning [systems], and so forth. Lynch: Everything. Foote: This is 11,000 meters. Ehrlich: Yeah, that's about as far as you go. [*Everybody laughs*] It's about right. Foote: Yeah. A follow-on question concerns looking at the total system. I know you've been involved in standards and callibration work for a long time. Can you tell us anything about that? Ehrlich: Not a whole lot, actually. I have been involved; but I've been involved in just making sure the thing stayed together and makes sense, but I don't remember a lot of that anymore. I've been involved, lately, with an IEEE standards committee and they have a new way of expressing [dates]. There's a new international dating system, which most of you probably are not using yet, but the year comes first and then the month and then the day. So today would be 08-11-05. Lynch: So, IEEE's turned everything on its head again. [*Everybody laughs*] Ehrlich: Well, the European standard had the date: day, month, and year; this is the year, month, and day. And it's not the year, day, or the month like we normally have been using. But they finally came to an agreement on that. Lynch: Are they going to make it a 4-digit year? Ehrlich: What? Lynch: Are they going to make it a 4-digit year, so we don't wind up with 08-08-08? Ehrlich: They can get away with 2 digits for the year. [*Lynch laughs*] If you want. As long as you know what century you're in. Lynch: I was going to say. Bob Frosch: For the next 90 years it'll be alright. [*Laughs*] Duda: All we need is 3, we don't need 4. We only need 3. Ehrlich: The answer is it can be a 4-digit year whenever you need it to be. Doutt: By the way, I like that system and I've been using it to label data for quite some time. And one of the nice things about it when you do a sort, I mean, when you list things alphabetically everything is in order. So, I heartily embrace it. Ehrlich: The thing is, that this is a never increasing deal, which is one nice thing about it. Doutt: Yeah. Foote: Yeah. It has a monotonic character. Someone in background: Monotonic, yeah. Foote: But certainly those first two digits, 20, that identifies... Ehrlich: No, no, no, no. Use 08. Foote: Yes, I know that, but it identifies it as a year. There are many 6-digit codes... Ehrlich: If you get into more than one century you have to use 2008, but you'd have to use that anyhow if you got into more than one century. Probably. Foote: Now you participated in the ASA standards work, I believe, for a very long time. Ehrlich: I may have, but I just don't remember much happening. Lynch: Must have been exciting. [*A few people laugh*] Ehrlich: I've forgotten details. Foote: Well, that is the reputation for standards work, but it is essential. And as soon as we discover incompatibilities then we realize that we are a victim of lack of attention to standards. We take it for granted that there are a lot of things that work only because of standards. Ehrlich: Well, the standards make life easier, or are intended to make life easier, so that people can understand each other without a long harangue. Foote: Much safer, too. Safer, also, use of electricity. Ehrlich: Yes. Yeah, true. Foote: I'd like to ask you about literature: what journals you read or you have read in the past. Do you maintain currency in certain areas? Ehrlich: Well, I still have a complete set of the Acoustical Journal back to 1929, but I'm trying to get that together with the help of my daughter and granddaughter because I think I'd like to give it away to somebody who can use it. Probably to Brown or something like that. Lynch: This is the complete paper set of the journals? [*Barbara Ehrlich nods head*] Lynch: Yep. Yeah, not so many of those around anymore. Duda: Wow. Lynch: Yeah. Ehrlich: I bought the back issues when they were made available, because I had only owned it from '49 on, originally, as a member. Foote: Well, this does still have value. The journal is now available electronically, but there are many examples that we encounter where the text - the electronic text - is not legible. Ehrlich: Oh, that's sure. Foote: The characters are too fine, or the original was more annotated, marked up [by hand]. Ehrlich: Oh yeah. Duda: Yeah. Foote: It [the non-annotated copy] was the only one available for scanning Ehrlich: That can happen. Foote: I hope the family's aware there is some value here. Barbara Ehrlich: Well, the family is happy to find a home for this. [*Everybody laughs*] Barbara Ehrlich: If you want to help us find a home for it I'd be happy. Foote: Yeah, I know I appreciate if you've found space issues for libraries. I hope you're successful. Ehrlich: When Barbara was living at home we had a cellar planted with a lot of journals. She probably remembers that. [*Barbara Ehrlich nods head*] Barbara Ehrlich: So, well, we can [talk later]. If anyone knows [anyone who wants the journals]. I'm happy to [give them away]. It's sitting there. Lynch: Have you talked to Elaine [?Moran?] and the Acoustical Society and stuff? Barbara Ehrlich: [*Shakes head*] I haven't done that. Lynch: You might...[want to talk to the]...Acoustical Society so they can have an extra archival copy... Duda: Could sell 'em. [*Laughs*] Lynch: ...or something like that because there's not... like Ken says, there's a few issues right now. I think if they had better copies they could probably be scanned and the rest of it. Barbara Ehrlich: OK. Lynch: I mean, the rest of us have worked overtime to actually eliminate some of our paper copies. But to have a couple of archival copies back would definitely be worth the trouble. Barbara Ehrlich: OK. Foote: I'm making a note of it. I would like to follow this up with you later. Barbara Ehrlich: Yeah, yeah. Yeah. Foote: And just talk about possible disposition. The Journal of the Oceanic Engineering Society, do you also have a complete set? Ehrlich: Of what? Foote: J.O.E? Lynch: Journal of Oceanic Engineering. Ehrlich: Oh. I know. I don't know. I think I've been throwing them out, lately. Barbara Ehrlich: One of my tasks is to look in the attic to see what is actually there. [*Jim Doutt laughs*] So that will happen this winter. Ehrlich: I was only Editor-in-Chief of that for 6 years. Lynch: Same here. Ehrlich: What? Lynch: Same here. 6 years is enough. Ehrlich: Well, I decided it was enough and they gave me a silver medal somewhere along the line or a citation or some sort from the Oceanic Engineering Society. Lynch: Actually, if you have back issues of that, that would be worth it, because there's not so many of those around. Barbara Ehrlich: I'll look. Ehrlich: I think it was mostly a certificate. Barbara Ehrlich: I'll definitely look in for you. Lynch: The Oceanic Engineering one, because that is actually a smaller collection. We've actually archived the whole thing right now, but again, to have an archival copy somewhere would be good. And I'd be happy to help you with that. Barbara Ehrlich: OK. Foote: Again, I've made a note of it to follow up. Barbara Ehrlich: We'll be in touch. Foote: Please, latch on to it. Lynch: Ken knows where we fall. Foote: I work with Jim. [*Points to Jim Lynch*] But hold on to it if you come across any journal issues. We're well up to date for current issues, since your tenure as Editor-in-Chief. [*Points to Jim Lynch, who nods his head*] But the 1980s that's a dark time for this journal. Barbara Ehrlich: I'll see what we have. Lynch: OK, If you have some, that'd be great. Foote: The publication run was very modest at that time. Ehrlich: I remember putting out an edition with just one paper in it because we hit a snag in getting the papers to come in. And I had a friend in Italy who was Associate Editor and he was slow in getting papers in. I finally got him to release, and then some of the papers that he'd been holding onto we finally finished off with - some of the papers that he finally sent me. But he was an Associate Editor and there'd been a fair amount of work going on over there and I just figured we ought to hone in on it. Lynch: This was somebody at the [?Saklans?] center? Ehrlich: So we did. But he was just holding out and holding out. Lynch: That happens. Ehrlich: And that's not the way to run a journal. Lynch: But that's typically what happens. Is a couple of Associate Editors that [?are high strung?]. Ehrlich: Better to make a mistake and publish one that was wrong than to hold up twenty. Frosch: Was he not working at it or was he waiting to make it perfect? There are usually two different reasons for it. Ehrlich: Well, you try to make sure there are no major mistakes. Lynch: That's the best you can do. Ehrlich: Right. If there's a major mistake you don't want to do anything with it, but if it's just a minor one you can sort of skim over it and assume that people will pick it up. Foote: Are there any other journals that you have made use of frequently in the past? Ehrlich: Not really. I occasionally looked at some of the other IEEE journals, I used to get a fair batch of them, but I don't anymore. Lynch: Do you still follow any active research areas, Stan? Do you still have some stuff? Ehrlich: I'm just retired. Lynch: Pretty much retired? Said "That was fun"? Ehrlich: I decided it was time for me to want to go. I'm 83 now. Lynch: Oh, I'm just wondering. Ehrlich: Last I told my daughter coming down here I'm working on 150. Lynch: We all are. Foote: Well, there's also some modesty here because you do participate in a ASA subcommittee on standards you're involved still in the IEEE SSC14 committee for standardization. Ehrlich: Yes. I still once in a while go to their meeting. Foote: And you write reviews for the Journal. [*Ehrlich tilts head indicating he couldn't hear*] Foote: You still do work for the Journal of the Acoustical Society. Ehrlich: No, I don't do work for any journal anymore now. I freed myself completely. Lynch: You gave it others. Ehrlich: They made me give it up in 2002. They told me I couldn't be an Associate Editor anymore because I'd already had 7 terms and I was only entitled to 3. [*Everybody laughs*] Foote: Umm... Ehrlich: You get that? Foote: Yeah. I meant to ask you, you mentioned earlier you met, or knew, Philip Morse. Philip Morse? Ehrlich: What? Yes, yes. I met Philip Morse when he was at MIT. Foote: Were you working together at all? Ehrlich: No, no. He was more or less retired about then, or about to retire. He still had an office there, so he was young enough to have an office but not old enough to be that active in doing anything. At Bolt, he eventually took over while I was still there, took over the laboratory (the acoustics lab). Foote: Did you know the acoustics group at Brown University? Of Robert [?Byer?]? Peter Westervelt? Arthur Williams? Bruce Lindsay? Ehrlich: Yeah, I knew all of them. Yeah, Williams too. Right. Foote: When you were... Ehrlich: The order was, I guess: Lindsay was the oldest, and Williams was next oldest, and [?Byer?] (who just passed away a week or so ago) was next oldest (he was 88), and Westervelt was the youngest of the bunch (he was about my age). Foote: While you were at Raytheon did you have... was there a discussion going on with that group at Brown? Did you have any common interests? Ehrlich: What? What? Foote: Were you also meeting with the Brown Physics Dept.? Did you have contact with [?Byer?], Westervelt, Williams? Ehrlich: When I was there? Foote: When you were at Raytheon. Ehrlich: Oh, when I was at Raytheon. Not appreciably. No. Foote: I believe Peter Westervelt did have contact, maybe with George Walsh, [in the] development of parametric sonar. Ehrlich: Yeah, he was involved with that. Lynch: You're not going to make a non-linear acoustician out of him here, Ken. I'm sorry. Frosch: When you were at Raytheon did you generally have contact with the academic acoustics world or did you operate really separately and only through the...? Ehrlich: Well, I was still active in the Acoustical Society. Frosch: Yeah, through the Society but not directly with the people. Ehrlich: Sorry. So, through the Society - that was my main deal - and I always maintained contact with the Lindsays. In fact, they used to have a summer home in Portsmouth, Rhode Island, which is on the same island I live on, and they moved to there after he retired. And my late wife and I used to pick them up and take them to the local acoustical meetings. And we even used to take Mrs. Lindsay to the meetings after Bruce died. They had a son in my class at Brown: Bob Lindsay. Foote: What was his career? Ehrlich: Who? Foote: Bob Lindsay. Ehrlich: I don't know what he did. I don't know. I don't know what he or his sister Evelyn did. Foote: But you were in mechanical engineering at the time? Ehrlich: What I was at Brown in my Bachelor's days I was training to be a mechanical engineer. And that just meant taking a couple courses in your senior year if you were a civil or electrical. Frosch: What brought you into acoustics? [*Ehrlich leans forward to hear better*] What brought you into acoustics? Ehrlich: I think Bruce Lindsay. Frosch: Bruce Lindsay? Ehrlich: I was attracted to him and probably, of course, I was attracted to acoustics because I was hard of hearing, even then. Frosch: Nobody had trouble hearing Bruce. [*Laughs*] Ehrlich: Well, I could hear a lot better than then I can now. I didn't need a hearing aid then. But now my right ear needs a hearing aid; the left ear is essentially totally deaf. It's a candidate for one of these CI implants, if I want one. Lynch: There you go. [*Laughs*] Ehrlich: And I've chosen not to. Foote: Well, I have covered all the topics that I had that I wanted to ask you about. Anyone else have anything? Ehrlich: I think you've covered most of my career. Lynch: Well, yeah, career stuff. Foote: Well, there are large areas I know we can't touch just because of the nature of your work with sonar at Raytheon Company. Ehrlich: Not too much. There's not that much you can't talk about at this point because most of it has been declassified that I worked with. Duda: Well, that's good. There are benefits to that declassification of these little tidbits. Ehrlich: We used to send people out on sea trips for a fair amount of the time. I didn't go very often once; I went once in a while. We used to have one fellow named Bill Gordon who used to go there (out to sea) quite frequently. And at one point I became his supervisor, as it turned out, and I had him go out to sea and he stayed over at my house occasionally when he was about ready to go out because he used to live in Belmont, Massachusetts. And he used to drive down to Portsmouth, which is a fair drive actually, but he had been there when I had been through all the Boston area, he was a little older than I was. Duda: How often is "fairly frequently"? Ehrlich: Who's talking? Duda: Over here. When you say he went to sea fairly frequently, how [often] is that? Twice a year or twice a month? Ehrlich: What? Duda: How many trips per year did he make? Ehrlich: How...? Duda: You said... Frosch: How many trips a year did he make? Duda: You said that he went to sea often... Ehrlich: Oh, I didn't go very often. Duda: Not you, but the other [guy]. Ehrlich: I went once or twice a year, that's about all. Duda: OK, well, some people would consider that a lot. Ehrlich: I didn't go a lot. Bill used to go several times a year. Duda: OK, because we have people here... Ehrlich: Every couple months he went out to sea. Duda: OK, because we have some people who go out maybe 20 times a year. Ehrlich: I went out more than once, but not too often. Foote: Were you involved in the search for the Thresher. Ehrlich: No. Foote: Because Raytheon had engineers on board at that time. Ehrlich: Yes. Foote: And there was a question about identifying the cause of the accident based on analysis of acoustic records. Ehrlich: I might have had something about it, but I wasn't involved very heavily. I don't remember too much about it. Foote: Do you remember, was there any contact at that [time], when you were at Raytheon between Submarine Signal Division and the Woods Hole Oceanographic Institution? Ehrlich: I don't know. There could well have been, but I don't know. Lynch: Not with you anyway. Ehrlich: What? Lynch: Not with you. Ehrlich: No. [*Shakes head*] Foote: OK. Are there any other questions? Was there something you wanted to tell us about that we haven't asked? Ehrlich: Well, I think you've covered everything. I can't think of something to tell you that wouldn't be repetitious. Doutt: I'm curious, so often... Ehrlich: What? Doutt: So often in research when studying something and by accident get on to something new. Did you have any experiences like that? [Where] just by chance you seem to discover something and go off in a different direction? Ehrlich: Well, again, I was involved with this deal of trying to find the location of somebody pinging at you. And that got me off in a direction that kept me busy for a while, keeping things straight - making it work with either a ferroelectric or [?ferromarine?] magnetic transducer, you can do it either way. Foote: Yeah. There is something else I'd like to ask you about. I remember talking with you [*Motions to Tim Stanton*], Tim, about the analog/digital transition. This had major impact. Ehrlich: The what digital...? Foote: Analog to digital. Ehrlich: Analog to digital, Ken? Foote: It was a revolution, and it certainly impacted Raytheon Company sonar work. Ehrlich: Some of it, but it didn't impact too much of it. I mean, most transducers would have stayed analog. [*Jim Lynch nods head*] It was when you go into the signal processing that you went digital, then that became important. And I got into it only very slightly because things weren't as digital in 1991 as they are now, even. Foote: I recall the Navy mandating digital processing and this was early 1970s, so that was a major time of transition. Ehrlich: Yes. Foote: But I guess you were so close to the transducer end [*Jim Lynch nods head*] that you were less effected by that. Ehrlich: Well, some things, because we did analog, if you used clipping. Duda: Ahh. Ehrlich: What? Duda: I see. Ehrlich: And you could get away with it, with a very small loss compared to the amount of expense you would have to pay to go digital. Stanton: I think the early beamformer - the DIMUS... Ehrlich: What? Stanton: The DIMUS? The beamformer? DIMUS? Beamformer? The one bit. I think you... Frosch: The DIgital MUltibeam Synthesizer. Stanton: Yes. Ehrlich: Oh, DIMUS. Yeah, yes. DIgital MUltibeam Steering. Stanton: Yes. I think that was one bit. Was that right? Frosch: Yeah, that was a one bit. Stanton: Yeah. Frosch: The [?clipped one?]. Ehrlich: Yeah, yes. Lynch: Mmhmm. Stanton: It worked very well, actually. Frosch: [?Greg Anderson?] Stanton: Yep, exactly. Foote: Well... Lynch: I'll just ask something, kind of more an impression: Since you've hung around the Oceanic Engineering Society and the Acoustical Society for a couple of decades, do you think things look more exciting years ago or they look just about the same now? Ehrlich: I think there are always exciting things going on and you just have to look for them and work with them. Things don't just start and end they just keep going. Lynch: Just wondering your impression. Good. Ehrlich: Some things get more attention than others, that's all. Foote: OK. Lynch: OK. Thank you, Stan. Thanks for coming over here. [*Everyone claps*] Ehrlich: I thank you for inviting me down here to talk with you and I've enjoyed it and its a good chance to relive some of my past life. Lynch: Oh, it's fine. Did you get a tour around here at all? Did you and Ken... Foote: No, but I will offer one. Ehrlich: No, but I think I want to head back. We have some plans Lynch: Oh, you have some? Barbara Ehrlich: Oh, well, we can have a short tour. Lynch: Do you have a few minutes? Ehrlich: What? Lynch: We can give you a little short tour around. Barbara Ehrlich: We can have a short tour. We have time. Ehrlich: Oh, we can have time? OK. We have time for a little tour. Lynch: Yeah? OK. Ehrlich: My daughter keeps good track of me. Lynch: Great, I think you'd enjoy that. I think you'd enjoy that, Stan.